BUT YOU HAVE COME TO MOUNT ZION AND TO THE CITY OF THE LIVING GOD THE HEAVENLY JERUSALEM: alla proseleluthate (2PRAI) Sion horei kai polei theou zontos (PAPMSG) Ierousalem epouranio: (Ps 2:6; 48:2; 132:13,14 Isa 12:6; 14:32; 28:16; 51:11,16; 59:20 Isa 60:14 Joel 2:32 Ro 11:26 Ga 4:26 Rev 14:1) (City - He 13:14 Ps 48:2, 87:3 Mt 5:35 Php 3:20 Rev 3:12, 21:2,10, 22:19) (Living God -  He 3:12, 9:14, 10:31 Dt 5:26 Jos 3:10 2Ki 19:4 Ps 42:2, 84:2, Jer 10:10 Da 6:26 Ho 1:10 Mt 16:16 Ro 9:26 1Th 1:9 Rev 7:2)

The writer's point in this section is that instead of returning to Mount Sinai, the Hebrew audience is urged to continue their approach to Mount Zion, the spiritual mountain and city where the living God dwells and reigns.

The Nelson Study Bible nicely summarizes this section noting that...

In these verses, the author of Hebrews contrasts the Mosaic covenant with the New Covenant by contrasting two mountains: Mount Sinai and Mount Zion. At Mount Sinai, the Israelites received the Law from God with fear and trembling, for God displayed at that time His awesome power (see Ex 19:10-20:26). In contrast, Christian believers have come to a heavenly Jerusalem on Mount Zion through Jesus’ blood. This mountain is a celebration of the Holy One, attended by angels, believers, and righteous people. The author makes the contrast between the two covenants vivid, and then once again exhorts his readers not to reject Christ’s offer of salvation (see Hebrews 12:25-29).(Radmacher, E. D., Allen, R. B., & House, H. W. The Nelson Study Bible: NKJV.  Nashville: Thomas Nelson)

Have come (4334) (proserchomai from prós = facing + erchomai = come) means literally to come facing toward and so to approach or come near. To come to visit or associate with. It describes the approach to or entry into a deity’s presence. In the Septuagint (LXX) proserchomai was the verb used to describe the approach of the priests to Jehovah for worship and to perform of their priestly (Levitical) functions. But here in Hebrews, under the New covenant, all seven uses of  proserchomai refer to believers possessing the privilege of access to God the Father through Christ the Great High Priest.

Here are the seven uses of this proserchomai in Hebrews...

Hebrews 4:16 (note) Let us therefore draw near with confidence to the throne of grace, that we may receive mercy and may find grace to help in time of need. (Comment: "Let us..." emphasizes that this privilege is always available to those under the New Covenant. Do we really comprehend and avail ourselves of the profundity of this privilege?)

Hebrews 7:25 (note) Hence, also, He is able to save forever those who draw near (present tense = emphasizes continual activity) to God through Him, since He always lives to make intercession for them.

Hebrews 10:1 (note) For the Law, since it has only a shadow of the good things to come and not the very form of things, can never by the same sacrifices year by year, which they offer continually, make perfect those who draw near.

Hebrews 10:22 (note) let us draw near with a sincere heart in full assurance of faith, having our hearts sprinkled clean from an evil conscience and our bodies washed with pure water.

Hebrews 11:6 (note) And without faith it is impossible to please Him, for he who comes (drawn near) to God must believe that He is, and that He is a rewarder of those who seek Him.

Hebrews 12:18 (note) For you have not come (drawn near) to  a mountain that may be touched and to a blazing fire, and to darkness and gloom and whirlwind,

Hebrews 12:22 (note) But you have come (drawn near) to Mount Zion and to the city of the living God, the heavenly Jerusalem, and to myriads of angels

The writer uses the perfect tense which views this heavenly possession of Mt Zion as already attained by those who have believed the new covenant and which is their continuing possession. In spirit they were residents of the city already, though in body they were strangers and aliens on earth. That there is yet to be an earthly manifestation of the city is clear from the later reference in Hebrews 13:14 to “the city which is yet to come.”

Mount Zion (see notes on Zion) is the site of Mt Moriah  (means "the place where Yahweh sees") where Abraham sacrificed Isaac and corresponds to the Dome of the Rock on Temple Mount. Many scholars feel that the Temple Mount area is in the approximate site of Mt Moriah where Abraham offered Isaac his "only son" whom he loved. Centuries later Mt Moriah was the site of the threshing floor of Ornan which David purchased for Solomon's temple (1Chr 21:18ff, 2Sa 24:24, 25, 2Chr 3:1] And nearby is another "mount" of sacrifice known as Golgotha (Jn19:17) also called Calvary (in same range as Moriah but slightly NW) on which God the Father offered up His only Son, the Son Whom He loved (Jn 3:16, 3:35)

Mount Zion was also the location of the Jebusite stronghold that David captured (2Sa 5:7) and made the religious center of his kingdom by bringing to it the golden Ark of God representing God’s presence with His people. This is the site on which Solomon later built the Temple and installed the Ark (1Ki 8:1).

Zion is synonymous with Jerusalem and thus this holy place became the earthly dwelling-place of God. In the new Covenant, believers in Christ have come to the heavenly counterpart, the Jerusalem from above.

Paul distinguished between the earthly and heavenly Jerusalem in his allegorical exposition on Hagar (and Ishmael, born according to the flesh) and Sarah (and Isaac, born according to the Spirit)...

Now this Hagar is Mount Sinai in Arabia, and corresponds to the present Jerusalem, for she is in slavery with her children. But the Jerusalem above is free; she is our mother. (Galatians 4:25-26) (Comment: The phrase Jerusalem which is above was familiar to the rabbinical teachers, who conceived the heavenly Jerusalem as the archetype of the earthly. On the establishment of Messiah’s kingdom, the heavenly archetype would be let down to earth, and would be the capital of the messianic theocracy.)

And so as depicted allegorically by Paul in Galatians 4, the Law (the Old Covenant) had its Mount Sinai but faith has its Mount Zion which is the same city which Abraham and the patriarchs sought, the writer of Hebrews recording that by faith (not sight) Abraham

was looking for the city which has foundations, Whose Architect and Builder is God... (see note Hebrews 11:10)

But as it is, they desire a better country, that is, a heavenly one. Therefore God is not ashamed to be called their God; for He has prepared a city for them (see note Hebrews 11:16).

John saw this city in his vision recording...

And I saw a new heaven and a new earth; for the first heaven and the first earth passed away, and there is no longer any sea. And I saw the holy city, new Jerusalem, coming down out of heaven from God, made ready as a bride adorned for her husband. (See notes Revelation 21:1; Revelation 21:2)

In one sense, this is still to come (see Hebrews 13:14-note, “but we are looking for the city that is to come”), but we have also already arrived there in spirit. In Ephesians for example Paul describes the heavenly position of believers writing that God has...

raised us up with Him (Christ), and seated us with Him (Christ, Who is at the right hand of the throne of God) in the heavenly places, in Christ Jesus (see note Ephesians 2:6)

Christians are now citizens of the heavenly city and enjoy its privileges. Paul wrote that believers are enrolled as citizens of heaven even while on earth Paul explaining that...

our citizenship is in heaven, from which also we eagerly wait for a Savior the Lord Jesus Christ (see note Philippians 3:20)

We are in Mount Zion by virtue of our incorporation in Christ as explained above. To reiterate, the use of the perfect tense (have come) emphasizes our permanent, continuing state. This is why the seemingly endless miles of life’s marathon and the inevitable heartbreak hills should not deter us from pressing on toward the goal, running the race with endurance.. We are both in Zion and yet at the same time are marching to Zion!

Law had its earthly Jerusalem but faith has its heavenly capital above. The city of the living God is in heaven, the city which has the foundations, whose Architect and Builder is God.

As someone has well stated...

We have already arrived in principle where in full reality we shall be forever. The future is already the present. In today we possess tomorrow. On earth we own Heaven.

AND TO MYRIADS OF ANGELS: kai muriasin aggelon:

Myriads (3461)(murias from muríos = very many, innumerable) means a myriad (an indefinitely great number) or ten thousand or simply a number that cannot be counted.

Wuest comments that...

The angels are introduced here because they are the usual accompaniment of God’s glory and ministers of His will.

The myriads of angels are referred to several times in Scripture. For example Moses records a "sighting" with which most of his Jewish readers would have been familiar...

And he said, "The LORD came from Sinai, And dawned on them from Seir; He shone forth from Mount Paran, And He came from the midst of ten thousand holy ones; At His right hand there was flashing lightning for them. (Dt 33:2) (Evidently there were myriads of holy ones with God on Mount Sinai as His right hand wrote the commandments for Israel on tables of stone.

Angels were present at the giving of the law Luke recording...

you who received the law as ordained by angels, and yet did not keep it." (Acts 7:53)

In a parallel passage Paul asks...

Why the Law then? It was added because of transgressions, having been ordained through angels by the agency of a mediator, until the seed should come to whom the promise had been made. (Galatians 3:19) (Comment: The account of the giving of the law through Moses on Mount Sinai in Exodus 19:9-25 makes no mention of angels. However as noted above Deuteronomy 33:2 does mention holy ones which is almost assuredly a reference to angels through whom the Law was ordained. See also Psalm 68:17).

And earlier in Hebrews the writer reminded his readers of...

the word spoken through angels (which) proved unalterable, and every transgression and disobedience received a just recompense (see notes Hebrews 2:2)

And as the writer of Hebrews asked rhetorically in the first chapter...

Are they (referring to angels) not all ministering spirits, sent out to render service for the sake of those who will inherit salvation? (See note Hebrews 1:14)

These angels are mighty flaming spirits passing in and out of our lives, moving around us and over us just as they did saints of old.

The Living God - a phrase repeated 28 times in the NASB...

Dt 5:26 'For who is there of all flesh, who has heard the voice of the living God speaking from the midst of the fire, as we have, and lived?

Josh 3:10 And Joshua said, "By this you shall know that the living God is among you, and that He will assuredly dispossess from before you the Canaanite, the Hittite, the Hivite, the Perizzite, the Girgashite, the Amorite, and the Jebusite.

1 Sam 17:26 Then David spoke to the men who were standing by him, saying, "What will be done for the man who kills this Philistine, and takes away the reproach from Israel? For who is this uncircumcised Philistine, that he should taunt the armies of the living God?"

1 Sam 17:36 "Your servant has killed both the lion and the bear; and this uncircumcised Philistine will be like one of them, since he has taunted the armies of the living God."

2 Ki 19:4 'Perhaps the LORD your God will hear all the words of Rabshakeh, whom his master the king of Assyria has sent to reproach the living God, and will rebuke the words which the LORD your God has heard. Therefore, offer a prayer for the remnant that is left.'"

2 Ki 19:16 "Incline Thine ear, O LORD, and hear; open Thine eyes, O LORD, and see; and listen to the words of Sennacherib, which he has sent to reproach the living God.

Psa 42:2 My soul thirsts for God, for the living God; When shall I come and appear before God?

Psa 84:2 My soul longed and even yearned for the courts of the LORD; My heart and my flesh sing for joy to the living God.

Isa 37:4 'Perhaps the LORD your God will hear the words of Rabshakeh, whom his master the king of Assyria has sent to reproach the living God, and will rebuke the words which the LORD your God has heard. Therefore, offer a prayer for the remnant that is left.'"

Isa 37:17 "Incline Thine ear, O LORD, and hear; open Thine eyes, O LORD, and see; and listen to all the words of Sennacherib, who sent them to reproach the living God.

Jer 10:10 But the LORD is the true God; He is the living God and the everlasting King. At His wrath the earth quakes, And the nations cannot endure His indignation.

Jer 23:36 "For you will no longer remember the oracle of the LORD, because every man's own word will become the oracle, and you have perverted the words of the living God, the LORD of hosts, our God.

Dan 6:20 And when he had come near the den to Daniel, he cried out with a troubled voice. The king spoke and said to Daniel, "Daniel, servant of the living God, has your God, whom you constantly serve, been able to deliver you from the lions?"

Dan 6:26 "I make a decree that in all the dominion of my kingdom men are to fear and tremble before the God of Daniel; For He is the living God and enduring forever, And His kingdom is one which will not be destroyed, And His dominion will be forever.

Hosea 1:10 Yet the number of the sons of Israel Will be like the sand of the sea, Which cannot be measured or numbered; And it will come about that, in the place Where it is said to them, "You are not My people," It will be said to them, "You are the sons of the living God."

Mat 16:16 And Simon Peter answered and said, "Thou art the Christ, the Son of the living God."

Mat 26:63 But Jesus kept silent. And the high priest said to Him, "I adjure You by the living God, that You tell us whether You are the Christ, the Son of God."

Acts 14:15 and saying, "Men, why are you doing these things? We are also men of the same nature as you, and preach the gospel to you in order that you should turn from these vain things to a living God, WHO MADE THE HEAVEN AND THE EARTH AND THE SEA, AND ALL THAT IS IN THEM.

Rom 9:26 "AND IT SHALL BE THAT IN THE PLACE WHERE IT WAS SAID TO THEM, 'YOU ARE NOT MY PEOPLE,' THERE THEY SHALL BE CALLED SONS OF THE LIVING GOD."

2 Cor 3:3 being manifested that you are a letter of Christ, cared for by us, written not with ink, but with the Spirit of the living God, not on tablets of stone, but on tablets of human hearts.

2 Cor 6:16 Or what agreement has the temple of God with idols? For we are the temple of the living God; just as God said, "I WILL DWELL IN THEM AND WALK AMONG THEM; AND I WILL BE THEIR GOD, AND THEY SHALL BE MY PEOPLE.

1 Tim 3:15 but in case I am delayed, I write so that you may know how one ought to conduct himself in the household of God, which is the church of the living God, the pillar and support of the truth.

1 Tim 4:10 For it is for this we labor and strive, because we have fixed our hope on the living God, who is the Savior of all men, especially of believers.

Heb 3:12 Take care, brethren, lest there should be in any one of you an evil, unbelieving heart, in falling away from the living God.

Heb 9:14 how much more will the blood of Christ, who through the eternal Spirit offered Himself without blemish to God, cleanse your conscience from dead works to serve the living God?

Heb 10:31 It is a terrifying thing to fall into the hands of the living God.

Heb 12:22 But you have come to Mount Zion and to the city of the living God, the heavenly Jerusalem, and to myriads of angels,

Rev 7:2 And I saw another angel ascending from the rising of the sun, having the seal of the living God; and he cried out with a loud voice to the four angels to whom it was granted to harm the earth and the sea,

An illustration - The little girl was happily humming a hymn as she dusted the furniture to help her mother.

“Mommie, will I be dusting God’s chair when I get to heaven, the way the hymn says?” she asked.

Mother looked up with surprise,

“Which hymn, honey?”

“And dust around the throne,” her little girl quoted.

It took a while before the mother learned that she was quoting a line from the hymn “Marching to Zion,” with the phrase, “and thus surround the throne”!

TO THE GENERAL ASSEMBLY AND CHURCH OF THE FIRST-BORN WHO ARE ENROLLED IN HEAVEN: kai ekklesia prototokon apogegrammenon (RPPMPG) en ouranois: (General - Ps 89:7, 111:1 Ac 20:28, Eph 1:22, 5:24, 25, 26, 27 Col 1:24 1Ti 3:5) (firstborn (KJV): Ex 4:22, 13:2 Dt 21:17 Ps 89:27 Jer 31:9 Jas 1:18 Rev 14:4) (Enrolled - Ex 32:32 Ps 69:28 Lk 10:20 Php 4:3 Rev 13:8, 20:15)

General assembly - note that in the Greek text paneguris is the last section of Hebrews 12:22 (see there) but is placed in verse 23 in the English.

General assembly (3831) (paneguris from pás = all, + águris  = an assembly from agora = public square, marketplace) is used only here in the NT to describe a solemn assembly convened for purposes of a happy, joyous festivity. The Greeks used paneguris to describe a festal gathering of the whole people to celebrate public games or other solemnities.

The verb form panegurizo is used in Isaiah where God declares...

Be joyful with Jerusalem and rejoice for her (Septuagint translates the Hebrew with the verb panegurizo = to celebrate a public festival), all you who love her; Be exceedingly glad with her, all you who mourn over her (Isaiah 66:10)

As explained below Jesus is the firstborn and by virtue of our union with Him we are firstborn sons of God. All the rights of inheritance go to the firstborn—to us who are “co-heirs with Christ” (Ro 8:17-note).

First-born (firstborn) (4416)(prototokos from protos = first, foremost, in place order or time; rank dignity + titko = beget, to bear, bring forth)  can mean first-born chronologically (Lk 2:7), but refers primarily to position, rank, priority of position and emphasizes quality or kind, not time with the idea of "preeminence".

Prototokos is used 8 times in the NT and four refer to Jesus -- Colossians 1:18  (note), Romans 8:29 (note), Hebrews 1:6  (note), and Revelation 1:5 (note) Each of these references to Christ as prototokos are in somewhat different contexts so be careful not to be confused. Vine helps untangle these uses by pointing out that in Colossians 1:18 (note) and Revelation 1:5 (note) firstborn refers to His resurrection, in Romans 8:29  (note) to His position in relationship to the Church, in Hebrews 1:6  (note) to His Second Advent when the word “again” is place in the right place (the Authorized Version gives a wrong translation, making the “again” seem to introduce a quotation, instead of signifying the second time when God will bring His Son into the world).

In Ps 89:27, God says of the Messiah that He "shall make him My first-born" then defines what He means—"the highest of the kings of the earth."

In the present verse the firstborn enjoy the rights of firstborn sons, because of their union with Christ, the Firstborn.

The assembly of the firstborn will have all Christians of all times as its members. It will have its first full assembly in the future age with the OT spirits of righteous men made perfect are together with NT saints forever. And thus this reference is to the whole communion of saints (all Christians of all times) who have come, not merely into the presence of the church, but into its membership by faith in Christ. The writing of their names in heaven recalls Jesus’ words to his disciples,

 Rejoice that your names are written in heaven (Lk 10:20).

They will all share with Jesus the title of firstborn (Col 1:18) because they are “heirs of God and coheirs with Christ” (Romans 8:17-note).

AND TO GOD, THE JUDGE OF ALL: kai krite theo panton: (God - He 6:10, 11, 12, 9:27, Ge 18:25, Ps 50:5,6, 94:2, 96:13, 98:9 Mt 25:31, 32, 33, 34 Jn 5:27 2Th 1:5, 6, 7 1Pe 2:23)

it is appointed for men to die once and after this comes judgment (Hebrews 9:27-note)

God is not unjust so as to forget your work and the love which you have shown toward His name, in having ministered and in still ministering to the saints. (see note Hebrews 6:10)

there is no creature hidden from His sight, but all things are open and laid bare to the eyes of Him with whom we have to do  (Hebrews 4:13-note).

And for those who reject Jesus' sacrifice and insult His Spirit of grace there remains no hope but instead...

a terrifying expectation of judgment and THE FURY OF A FIRE WHICH WILL CONSUME THE ADVERSARIES (Hebrews 10:27-note)

For we know Him Who said, "VENGEANCE IS MINE, I WILL REPAY." And again, "THE LORD WILL JUDGE HIS PEOPLE." It is a terrifying thing to fall into the hands of the living God.  (Hebrews 10:30, 31-notes).

This relief from the fear of judgment is an enormous blessing to those who know themselves to be (saved) sinners in thought, word and deed.

AND TO THE SPIRITS OF RIGHTEOUS MEN MADE PERFECT: kai pneumasi dikaion teteleiomenon (RPPMPG): (Spirits - He 11:4,40 Eccl 12:7 1Co 13:12, 15:49,54, 2Co 5:8 Php 1:21, 22, 23, Php 3:12-21, Col 1:12 Rev 7:14, 15, 16, 16, 17)

Hebrews 11:40 -note (apart from us they should not be made perfect)

Since they are spirits, they are those who have died but have not yet been resurrected. Since they are just men made perfect, certainly they refer to the Old Testament saints who could not be made perfect before Christ’s time (Hebrews 11:40-note); but now, they have been made perfect through His one sacrifice (Hebrews 10:14-note). (Dobson, E G, Charles Feinberg, E Hindson, Woodrow Kroll, H L. Wilmington: KJV Bible Commentary: Nelson or Logos)

Made perfect (5048) (teleioo related to teleios from telos = an end, a purpose, an aim, a goal, consummate soundness, idea of being whole) means to accomplish or bring to an end or to the intended goal (telos). It means to be complete, mature, fully developed, full grown, brought to its end, finished, wanting nothing necessary to completeness or in good working order. It does not mean simply to terminate something but to carry it out to the full finish which is picked up in the translation "perfected".

Teleioo signifies the attainment of consummate soundness and includes the idea of being made whole. Interestingly the Gnostics used teleios of one fully initiated into their mysteries and that may have been why Paul used teleios in this epistle.

In He 12:2 (see note) Jesus is designated as "the author and perfecter of faith" where perfecter is teleiotes, the Completer, the One Who reached the goal so as to win the prize so to speak.

How are the spirits of righteous men made perfect? They have, like the Author of their faith, finished their earthly race and attained the goal (and their reward.) (Philippians 3:14-note) Brought to the goal, to perfection (Hebrews 5:9-note). The "goal" of our earthly life is to finish this present life's race with grace, holding fast the faith, enduring to the end.

Wuest has this note on the NT word group (telos, teleioo, teleios, teleiosis, teleiotes)...

Teleios the adjective, and teleioo the verb. The adjective is used in the papyri, of heirs being of age, of women who have attained maturity, of full-grown cocks, of acacia trees in good condition, of a complete lampstand, of something in good working order or condition. To summarize; the meaning of the adjective includes the ideas of full-growth, maturity, workability, soundness, and completeness. The verb refers to the act of bringing the person or thing to any one of the aforementioned conditions. When applied to a Christian, the word refers to one that is spiritually mature, complete, well-rounded in his Christian character.

Richards commenting on the word group (telos, teleioo, teleios, teleiosis, teleiotes) writes that

These words emphasize wholeness and completeness. In the biological sense they mean "mature," or "full grown": the person, animal, or plant achieved the potential inherent in its nature. The perfect is the thing or person that is complete, in which nothing that belongs to its essence has been left out. It is perfect because every potential it possesses has been realized. (Richards, L O: Expository Dictionary of Bible Words: Regency)

Telioo is used 19 times of 24 total NT uses in Hebrews, often in the sense of to make perfect or fully cleanse from sin in contrast to ceremonial (Levitical) cleansing. The writer is emphasizing the importance of perfection... (which should cause any Jew who is contemplating the worth of Christ and the New Covenant to realize his utter hopelessness to every attain perfection under the Old Covenant).

Hebrews 2:10 (note) For it was fitting for Him, for Whom are all things, and through Whom are all things, in bringing many sons to glory, to perfect the author of their salvation through sufferings. (Comment: This does not imply any moral imperfection in the Lord Jesus, but speaks of the consummation of the human experience of suffering the death of the Cross, through which He must pass if He is to become the Author or Captain of our salvation.)

Hebrews 5:9 (note) And having been made perfect, He became to all those who obey Him the source of eternal salvation,

Hebrews 7:19 (note) (for the Law made nothing perfect), and on the other hand there is a bringing in of a better hope, through which we draw near to God. (Comment: This means to carry through completely, to make complete, to finish, bring to an end. The old covenant could bring nothing to conclusion. The Mosaic economy could reveal sin but it could never remove sin, and so it had to be removed. It gave no security. It gave no peace. A man never had a clean conscience.)

Hebrews 7:28 (note) For the Law appoints men as high priests who are weak, but the word of the oath, which came after the Law, appoints a Son, made perfect forever.

Hebrews 9:9 (note) which is a symbol for the present time. Accordingly both gifts and sacrifices are offered which cannot make the worshiper perfect in conscience,

Hebrews 10:1 (note) For the Law, since it has only a shadow of the good things to come and not the very form of things, can never by the same sacrifices year by year, which they offer continually, make perfect those who draw near. (Contrast with Jesus in Hebrews 5:9 above.  The idea in Hebrews 10:1 is that the ceremonial law could not actually save the believer. Its work was always short of completeness.)

Hebrews 10:14 (note) For by one offering He has perfected  for all time those who are sanctified. (Comment: Wuest writes "Here, the completeness of the state of salvation of the believer is in view. Everything essential to the salvation of the individual is included in the gift of salvation which the sinner receives by faith in Messiah’s sacrifice. The words “for ever” here are to be construed with “perfected.” It is a permanent state of completeness in salvation to which reference is made. The words “them that are sanctified” are descriptive of the believer. He is one set apart for God) (ibid)

Hebrews 11:40 (note) because God had provided something better for us, so that apart from us they should not be made perfect.

Hebrews 12:23 (note) (But you have come...) 23 to the general assembly and church of the first-born who are enrolled in heaven, and to God, the Judge of all, and to the spirits of righteous men made perfect,

In sum the fundamental idea of telioo is the bringing of a person or thing to the goal fixed by God.

It is interesting and doubtless no mere coincidence that in the Septuagint (LXX) teleioo is translated numerous times as consecrated or consecration, especially speaking of consecration of the priests (cf Jesus our "great High Priest") (Ex 29:9, 29, 33, 35 Lev 4:5; 8:33; 16:32; 21:10; Nu 3:3). The LXX translators gave the verb teleioo a special sense of consecration to priestly service and this official concept stands behind the writer's use in this passage in Hebrews 5:9 (note). It signifies that Jesus has been fully equipped to come before God in priestly action.

Study the other 15 NT uses of telioo (other than the 9 in Hebrews)

Luke 2:43 and as they were returning, after spending the full number of days, the boy Jesus stayed behind in Jerusalem. And His parents were unaware of it,

Luke 13:32 And He said to them, "Go and tell that fox, 'Behold, I cast out demons and perform cures today and tomorrow, and the third day I reach My goal.' (Comment: "Today and tomorrow and the third day" means that God's timetable is unfolding for Jesus, and no king like Herod could shorten the time. When His work is accomplished or has reached its intended goal, His death and resurrection will be its perfection.)

John 4:34 Jesus said to them, "My food is to do the will of Him who sent Me, and to accomplish His work. (Comment: Teleioo does mean just to bring to an end but to perfect it. The work He had been sent to do was finished on the Cross, and thus He cried "It is finished! [ = related verb teleo]" John 19:30. Note that Jesus is not saying that He refrained from eating food but that the great goal of His life was not to cater to His body but rather to the will of His Father! Which do you cater to? Are you accomplishing His work in and through you? see note Ephesians 2:10)

John 5:36 "But the witness which I have is greater than that of John; for the works which the Father has given Me to accomplish, the very works that I do, bear witness of Me, that the Father has sent Me. (Comment: The Old Testament testifies to the mission and ministry of Jesus precisely what God said He would do in Scripture and what God told Jesus to do as He ministered.)

John 17:4 "I glorified Thee on the earth, having accomplished the work which Thou hast given Me to do.

Comment: Jesus had finished His work of teaching and witness, but His work of redemption had yet to be accomplished on the cross. He would then shout the great victory cry: "It is finished!" John 19:30

J C Ryle explains how the Cross accomplished God's perfect will "The crucifixion brought glory to the Father. It glorified His wisdom, faithfulness, holiness, and love. It showed Him wise, in providing a plan whereby He could be just, and yet the justifier of the ungodly.—It showed Him faithful in keeping His promise, that the seed of the woman should bruise the serpent’s head.—It showed Him holy, in requiring His law’s demands to be satisfied by our great Substitute.—It showed Him loving, in providing such a Mediator, such a Redeemer, and such a Friend for sinful man as His co-eternal Son."

John 17:23 I in them, and Thou in Me, that they may be perfected in unity, that the world may know that Thou didst send Me, and didst love them, even as Thou didst love Me. (Comment: "In unity" is literally “unto oneness” and represents the goal of the perfecting action, that goal being believers might be in a state of having achieved the unity intended for them; one which reflects the unity between the Father and the Son)

John 19:28 After this, Jesus, knowing that all things had already been accomplished (related verb teleo), in order that the Scripture might be fulfilled (teleioo), said, "I am thirsty." (Comment: Here Scripture "reaches it's goal" or is fulfilled in Jesus.)

Acts 20:24 "But I do not consider my life of any account as dear to myself, in order that I may finish my course (dromos = race, the course of one's life), and the ministry which I received from the Lord Jesus, to testify solemnly of the gospel of the grace of God.

2 Corinthians 12:9 And He has said to me, "My grace is sufficient (IS = It already is - we don't need to ask Him for more. We need to abide in the sufficiency of what He has already provided) for you, for power is perfected in weakness." Most gladly, therefore, I will rather boast about my weaknesses, that the power of Christ may dwell in me.

Philippians 3:12 (note) Not that I have already obtained it, or have already become perfect (perfect tense) (reached my goal, accomplished), but I press on in order that I may lay hold of that for which also I was laid hold of by Christ Jesus.

Comment: He was not yet perfectly conformed to Christ. The process was still going on. Note that perfect tense speaks of an action that was completed in past time, having results that exist in present time. The past completed action of teleioo would refer to the work of the Holy Spirit bringing the saint to that place of spiritual maturity in which the sanctifying process would have done its work so well that nothing needed to be added. In other words, the saint would be brought to a place of absolute spiritual maturity beyond which there is no room for growth and the results of this work would be permanent, and there would be no possibility of slipping back into a state of spiritual immaturity again. Obviously this perfection will only be fully achieved when we are glorified.

James 2:22 You see that faith was working with his works, and as a result of the works, faith was perfected;

1 John 2:5 but whoever keeps His word, in him the love of God has truly been perfected. By this we know that we are in Him:

1 John 4:12 No one has beheld God at any time; if we love one another, God abides in us, and His love is perfected in us. (Comment: Wuest writes that "If saints have this agape love habitually for one another, that shows that this love which God is in His nature, has accomplished its purpose in their lives. It has made us loving and self-sacrificial in our characters. This love has been brought to its human fulness in the lives of the saints. The verb “is perfected” is perfect in tense, speaking of a past completed act having present results.)  (ibid)

1 John 4:17 By this, love is perfected with us, that we may have confidence in the day of judgment; because as He is, so also are we in this world.

1 John 4:18 There is no fear in love; but perfect love casts out fear, because fear involves punishment, and the one who fears is not perfected in love.

AND TO JESUS THE MEDIATOR OF A NEW COVENANT: kai diathekes neas mesite Iesou: (Jesus - He 7:22, 8:6,8, 1Ti 2:5) (New - He 13:20, Isa 55:3 Jer 31:31, 32, 33) (Covenant - He 9:15 Mt 26:28 Mk 14:24 Lk 22:20 )

Mediator (3316) (mesites from mesos = middle, in midst) describes who stands in the middle between two people and brings them together. The covenant Christ mediates is a better covenant, since it is enacted on better promises. In Hebrews 8:6-13, the New Covenant is contrasted with the first covenant (Heb 8:7), the Mosaic Law (Ex 19:5). Christ's blood is the basis of the New Covenant and pays for the sins of all (Mt 26:28). Christians are ministers of the New Covenant (2 Cor 3:6). There will be an aspect of fulfillment in relation to Israel in the Millennium. Remember that the New Covenant was first given in the Old Testament to Israel, not to the Gentiles and not to the Church. God declares...

"Behold, days are coming," declares the LORD, "when I will make a new covenant with the house of Israel and with the house of Judah (if one reads this verse literally, clearly the New Covenant is first made to Israel and Judah), 32 not like the covenant which I made with their (the Jewish) fathers in the day I took them by the hand to bring them out of the land of Egypt (the first covenant = Mosaic covenant), My covenant which they broke, although I was a husband to them," declares the LORD.  33 "But this is the covenant which I will make with the house of Israel after those days," declares the LORD, "I will put My law within them (Israel) and on their (Israel's) heart I will write it; and I will be their God, and they shall be My people. 34 "And they shall not teach again, each man his neighbor and each man his brother, saying, 'Know the LORD,' for they shall all know Me, from the least of them to the greatest of them," declares the LORD, "for I will forgive their iniquity, and their sin I will remember no more." (When will these promises be fulfilled? See discussion of Romans 11:26 where Paul teaches that all Israel will be saved)
35 Thus says the LORD, Who gives the sun for light by day, and the fixed order of the moon and the stars for light by night, Who stirs up the sea so that its waves roar; The LORD of hosts is His name:
36 "If this fixed order (Sun, moon, stars) departs from before Me," declares the LORD, "Then the offspring of Israel also shall cease From being a nation before Me forever." (This verse substantiates the certainty of God's promises to Israel. The church has not replaced Israel. The sun, moon, and stars are still in their order, thus God's promises stand in effect.)
37 Thus says the LORD, "If the heavens above can be measured, And the foundations of the earth searched out below, Then I will also cast off all the offspring of Israel For all that they have done," declares the LORD.
38 "Behold, days are coming," declares the LORD, "when the city shall be rebuilt for the LORD from the Tower of Hananel to the Corner Gate. (see Jer. 31:31-34).

The writer of Hebrews had used this word in chapter 8 to contrast with the Old Covenant writing...

But now He has obtained a more excellent ministry, by as much as He is also the mediator of a better covenant, which has been enacted on better promises.

In first Timothy Paul writes that ...

there is one God, and one mediator also between God and men, the man Christ Jesus (1 Timothy 2:5)

New (3501)(neos) signifies new in respect to time (contrast kainos = new in respect to quality - the "New Covenant" is both!). Neos describes that which has recently come into existence but for a relatively short time. This temporarily and qualitatively new covenant is a better covenant of which Jesus is the Guarantee and Mediator, the writer explaining that...

(Jesus as a Priest forever) so much the more (than the Levitical priests) also Jesus has become the guarantee of a better covenant. (Hebrews 7:22-note)

But now He has obtained a more excellent ministry, by as much as He is also the mediator of a better covenant, which has been enacted on better promises. (Hebrews 8:6-note)

And for this reason He is the mediator of a new covenant, in order that since a death has taken place for the redemption of the transgressions that were committed under the first covenant, those who have been called may receive the promise of the eternal inheritance. (Hebrews 9:15-note)

Covenant (1242) (diatheke [word study] from dia = two + tithemi = to place pictures that which is placed between two Thus, a covenant is something placed between two, an arrangement between two parties.) was a commonly used in the Greco-Roman world to define a legal transaction in settling an inheritance. 

Diatheke denotes an irrevocable decision, which cannot be cancelled by anyone. A prerequisite of its effectiveness before the law is the death of the disposer and thus diatheke was like a "final will and testament".  In reference to the divine covenants, such as the Abrahamic covenant, diatheke is not a covenant in the sense that God came to agreement or compromise with fallen man as if signing a contract. Rather, it involves declaration of God’s unconditional promise to make Abraham and his seed the recipients of certain blessings.

AND TO THE SPRINKLED BLOOD WHICH SPEAKS BETTER THAN THE BLOOD OF ABEL: kai haimati rhantismou kreitton lalounti (PAPNSD) para ton abel: (Blood - He 9:21, 10:22, 11:28, Ex 24:8 1Pe 1:2) (Speaks  He 11:4 Ge 4:10 Mt 23:35 Lk 11:51)

the main reference would be to Abel’s sacrifice, offered in faith, though his murder, considered as a “sacrifice” of himself, would not be excluded. (Ellingworth, P., & Nida, E. A. A Handbook on the Letter to the Hebrews. UBS Handbook Series. New York: United Bible Societies. or Logos)

William MacDonald offers an excellent compromise noting that...

His (Christ's) precious blood is contrasted with the blood of Abel. Whether we understand the latter as meaning the blood of Abel’s sacrifice or Abel’s own blood which was shed by Cain, it is still true that Christ’s blood speaks more graciously. The blood of Abel’s sacrifice said, “Covered temporarily”; Christ’s blood says, “Forgiven forever.” Abel’s own blood cried, “Vengeance”; Christ’s blood cries, “Mercy, pardon, and peace.” (Bolding added) (MacDonald, W & Farstad, A. Believer's Bible Commentary: Thomas Nelson or Logos)

J Vernon McGee (As do John Calvin, Thomas Constable, ) clearly favors the blood of Abel as referring to Abel's literal blood...

Abel - Jesus' commentary on Abel in Mt 23:35 clearly refers to the literal blood of Abel for as our Lord said to the Jewish multitudes and His disciples...

"Therefore, behold, I am sending you prophets and wise men and scribes; some of them you will kill and crucify, and some of them you will scourge in your synagogues, and persecute from city to city, that upon you may fall the guilt of all the righteous blood shed on earth, from the blood of righteous Abel to the blood of Zechariah, the son of Berechiah, whom you murdered between the temple and the altar. (Mt 23:34, 35)

This declaration would certainly justify interpreting the "blood of Abel" here in Hebrews 12:24 as referring to Abel's literal blood.

Clearly Abel was justified (declared righteous) by grace through faith in the gospel of Jesus Christ (see the Protevangelium, or "first giving of the good news" by God in Genesis 3:15)

And I will put enmity Between you and the woman, And between your seed and her seed; He shall bruise you on the head, And you shall bruise him on the heel."

So Abel had heard the gospel in some form (we know from Galatians 3:8 the gospel was presented to Abraham) and responded to the good news in faith ("By faith Abel offered to God a better sacrifice than Cain, through which he obtained the testimony that he was righteous" - Hebrews 11:4-note) in contrast to Cain who responded in works and disobedience (and rebellion). 

Interpreting Hebrews 12:24 as a reference to Abel's murder, one can say that Abel was slain but he still speaks (Mt 23:35, Hebrews 11:4-note). Abel’s own shed blood cried out to the Lord for justice and judgment, but Jesus’ blood procures redemption and forgiveness, something better than Abel’s blood. Moses writes...

(God to Cain) And He said, "What have you done? The voice of your (Abel's) brother's blood is crying to Me from the ground. (Ge 4:10).

It is little wonder, that Augustine and many other early Christian exegetes, interpreted Cain as symbolic of the envious "Jews by whom Christ was slain" while Christ Himself “the Shepherd of the flock of men, [is] prefigured in Abel, the shepherd of the flock of sheep". This type of far fetched interpretation has caused many to shy away from the study of valid Old Testament types (See related discussion - Typology - Study of Biblical types) Clearly Augustine's (and other's) allegorical interpretation is incorrect. What is even more tragic is that misinterpretation of the Word of Truth invariably leads to misapplication. This allegorical interpretation of Cain is an excellent case in point for it has been misapplied by some to justify their "right" to punish the Jews (cf pogroms, holocaust, etc). Such aberrant interpretations emphasize the need for Spirit taught, intellectually honest interpretation of the Word of Truth, Inductive Bible study being one of the best modalities to achieve this end. (See discussion of the individual facets of inductive study - Observation, Interpretation, Application)