Circumcision of the Heart

EXTERNAL vs INTERNAL 
CIRCUMCISION

INDEX:

INTRODUCTION: While God had indeed commanded external circumcision of the foreskin as a sign of entrance into the Abrahamic covenant, the deeper significance was that this physical act was intended to be an manifestation of the obedience that flowed from one's faith (see discussion of the relationship to faith and obedience here and here). In other words, the physical act of circumcision was to reflect one's belief in the Abrahamic Covenant and the "Gospel" that had been preached to Abraham. In Galatians 3:8 Paul taught that "the Scripture, foreseeing that God would justify the Gentiles by faith, preached the gospel beforehand to Abraham, saying, “ALL THE NATIONS SHALL BE BLESSED IN YOU.” He later added "Now the promises were spoken to Abraham and to his seed (singular). He does not say, “And to seeds (plural),” as referring to many, but rather to one, “And to your seed (singular),” that is, Christ." (Gal 3:16-see note) The reader should be aware of the fact that in the original Hebrew the word descendants (or seed) is more literally the word "seed" and each use in the following passages is in the masculine singular which would be compatible with Paul's explanation in Galatians 3:16 that the reference was not to seeds plural but to Seed singular (masculine), specifically a reference to the Messiah (Study the following passages that speak of the "descendants" [the seed - every occurrence of descendants or seed is in the masculine singular] = Ge 12:7 13:15,16 15:5 17:7,8 21:12 22:17,18 26:3,4 28:13, 14 until the "Seed" culminates in Ge 49:10-see comment). Thus belief in the the promise which Jehovah gave to Abraham was tantamount to belief in the promised Seed, the coming Messiah. That belief resulted in an internal circumcision of the believing person's spiritual heart which was shown to be a true spiritual circumcision by their willingness to perform the physical circumcision. The latter (physical circumcision) was always intended to be a sign pointing to the former (spiritual circumcision)! Unfortunately, fallen men (all mankind Ro 5:12-note) seek to come to God their own way, via their works of presumed righteousness (which are really "filthy rags" Isa 64:6-notenote or here). The result was that many in the Jewish nation perverted the sign of circumcision (Ge 17:11) as a "work" which they taught merited salvation. In short, the sign in essence became the covenant instead of that which pointed to the covenant (see how one might misinterpret Ge 17:13 for example but to do so is to take it out of the context of the "whole counsel" of God's Word and a text out of context is a pretext [pretense]!).

As an aside there is surprisingly only one use of the actual word circumcision in the Old Testament, and it is found in a somewhat enigmatic passage that refers to Moses failure to circumcise his son, which drew a harsh rebuke from his wife "So He let him alone. At that time she said, "You are a bridegroom of blood "-- because of the circumcision." (Exodus 4:26) The Net Bible has an interesting note - "The Hebrew simply has lammulot ("to the circumcision[s]"). The phrase explains that the saying was in reference to the act of circumcision. Some scholars speculate that there was a ritual prior to marriage from which this event and its meaning derived. But it appears rather that if there was some ancient ritual, it would have had to come from this event. The difficulty is that the son is circumcised, not Moses, making the comparative mythological view untenable. Moses had apparently not circumcised Eliezer. Since Moses was taking his family with him, God had to make sure the sign of the covenant was kept. It may be that here Moses sent them all back to Jethro 'Ex 18:2) because of the difficulties that lay ahead." (See Why was God going to kill Moses in Exodus 4:24-26?)

Romans 2:26-note For indeed circumcision is of value, if you practice the Law; but if you are a transgressor of the Law, your circumcision has become uncircumcision. 26 If therefore the uncircumcised man keeps the requirements of the Law, will not his uncircumcision be regarded as circumcision? 27-note And will not he who is physically uncircumcised, if he keeps the Law, will he not judge you who though having the letter of the Law and circumcision are a transgressor of the Law? 28 For he is not a Jew who is one outwardly; neither is circumcision that which is outward in the flesh. 29 But he is a Jew who is one inwardly; and circumcision is that which is of the heart, by the Spirit, not by the letter; and his praise is not from men, but from God.

Due to the passing down of teaching from one rabbi to another over the centuries ("traditions of men") the true meaning and requirement of circumcision had been lost. And so by the 1st century we find rabbinical "traditions" teaching such fallacies as:

No circumcised Jewish man will see hell” and “Circumcision saves us from hell.”

The Midrash says

God swore to Abraham that no one who was circumcised would be sent to hell. Abraham sits before the gate of hell and never allows any circumcised Israelite to enter.

Here Paul Paul corrects this serious error in rabbinical interpretation and also explains the somewhat enigmatic OT passages alluding to "circumcision of the heart", clearly stating that it is a spiritual circumcision performed by the Holy Spirit at the time one receives the Messiah as Savior. It is salvation by grace through faith -- in the OT it was placing one's faith in a prophesied, promised Deliverer as one looked forward to the Cross of Messiah and in the NT it is looking back to Messiah's finished work of redemption at Calvary. Colossians 2:11 (below) also amplifies the true meaning of the circumcision that God has always desired.

And so in Romans 2:28, 29 Paul seeks to correct this "eternally fatal" flaw in the rabbi's misinterpretation - physical circumcision never saved anyone! Paul also helps us understand the somewhat enigmatic OT passages alluding to "circumcision of the heart". Based on Paul's teaching, we can see that the OT was clearly calling for a spiritual circumcision performed by the Holy Spirit at the time one received the Messiah as their Savior. In the Old Testament, this spiritual transaction transpired when one entered the Abrahamic Covenant by grace through faith. Similarly, in the New Testament the spiritual circumcision transpired when one entered the New Covenant by grace through faith. In other words, in the Old Testament, salvation (circumcision of one's heart) was achieved by placing one's faith in the prophesied Messiah, even as their "eyes of faith" looked forward toward the Cross of Messiah (at which time He "cut" the New Covenant). How much of the work of Christ on the Cross the Old Testament believers understood is uncertain. One thing is certain - they knew enough to be genuinely saved! And we in the NT (the "church age") with eyes of faith (Heb 11:1-note, 2Co 5:7) look back toward Messiah's finished work of redemption at Calvary (Jn 19:30-note).

Colossians 2:9 (see notes Colossians 2:9-10, 2:11-12) For in Him all the fulness of Deity dwells in bodily form, 10 and in Him you have been made complete, and He is the head over all rule and authority; 11 and in Him you were also circumcised with a circumcision made without hands, in the removal of the body of the flesh by the circumcision of Christ; 12 having been buried with Him in baptism, in which you were also raised up with Him through faith in the working of God, who raised Him from the dead.

Circumcision is a cutting away of something and therefore signifies a removal of that which has been cut away. In this verse Paul is clearly using the well known procedure of circumcision not to describe the physical act but ["without hands"] to describe spiritual circumcision. Here Paul uses the circumcision metaphor to explain the same spiritual transaction he discussed in Romans 6:1-11(notes) which describes in detail of the events that occurred when we placed our faith in Christ. At that very moment we were "circumcised with a circumcision made without hands", we were "baptized into Christ" (Galatians 3:27 = identified with Christ) and we experienced a death, burial and resurrection by virtue of our very real spiritual union with Christ. (Col 2:11, 12, 13-notes)

Regarding the "removal of the body of the flesh" the Greek verb gives us the picture of taking off and putting away clothes. And so by analogy "the body of the flesh" is taken off like an old garment (by the Spirit at the time of salvation when Galatians 3:27 teaches we "clothed ourselves with Christ", we exchanged our filthy rags of righteousness for His garment of righteousness). At the moment of salvation, the "body of the flesh" was put off in the sense that it was rendered inoperative (Ro 6:6-note) and now can no longer reign like a cruel dictator over believers as it did when we were unregenerate. The ruling power of this old sinful nature has been broken (Ro 6:7-note, Ro 6:12,13, 14-note , Ro 6:18-note, Ro 6:22- note). Note that the evil nature is not eradicated, for we still sin, but the power of Sin (our old "dictator") has been broken, and as we yield to and are led by the Spirit of Christ (Ro 8:14- note Romans 8:14) we are enabled to walk in the power of the Spirit (Ro 8:4, 5, 6- notes 8:4, 8:5, 8:6) and "by the Spirit" to put "to death the deeds of the body" (note on Ro 8:13). "The flesh" now can exert no more power over a believer than he or she allows it to have.

In short the distinguishing features of the circumcision made without hands are:

(1) not external but internal and not made with hands,

(2) It divests not of part of the flesh, but of the whole body of carnal affections (the power of sin has been rendered inoperative so now we truly can say "no") and

(3) this circumcision is not of Moses nor of Abraham but of Christ.

Ray Stedman - "I will never forget an incident that occurred a number of years ago here at the church. A young man came to my office carrying a thick Bible under his arm, which he had been reading. Looking at me very earnestly, he said to me, "Would you circumcise me?" After I had picked myself up from the floor, I explained to him why, one, he did not need physical circumcision, and, two, what circumcision meant. I pointed out that it was an eloquent symbol when it was properly understood." (Beware! Colossians 2:8-15)

MacDonald on "circumcision made without hands") - "This circumcision speaks of death to the fleshly nature. It is true positionally of every believer (the moment we receive Jesus as Lord and Savior), but should be followed by a practical mortifying of the sinful deeds of the flesh (Col 3:5-note). The apostle speaks of believers as the true circumcision (Phil. 3:3), in contrast to a party of Jewish legalists known as “the circumcision” (Gal. 2:12).(Believer's Bible Commentary) (Bolding added)

Genesis 17:9 God said further to Abraham, "Now as for you, you shall keep My covenant, you and your descendants after you throughout their generations. 10 "This is My covenant, which you shall keep, between Me and you and your descendants after you: every male among you shall be circumcised. 11 "And you shall be circumcised in the flesh of your foreskin; and it shall be the sign of the covenant between Me and you. 12 "And every male among you who is eight days old shall be circumcised throughout your generations, a servant who is born in the house or who is bought with money from any foreigner, who is not of your descendants. 13 "A servant who is born in your house or who is bought with your money shall surely be circumcised; thus shall My covenant be in your flesh for an everlasting covenant. 14 "But an uncircumcised male who is not circumcised in the flesh of his foreskin, that person shall be cut off from his people; he has broken My covenant."

Circumcision (cutting away the male foreskin) was not entirely new in this period of history, but the special religious and theocratic significance then applied to it was entirely new, thus identifying the circumcised as belonging to the physical and ethnical lineage of Abraham (cf. Acts 7:8; Ro 4:11). Without divine revelation, the rite would not have had this distinctive significance, thus it remained a theocratic distinctive of Israel (cf. v13). There was a health benefit, since disease could be kept in the folds of the foreskin, so that removing it prevented that. Historically, Jewish women have had the lowest rate of cervical cancer. But the symbolism had to do with the need to cut away sin and be cleansed. It was the male organ which most clearly demonstrated the depth of depravity because it carried the seed that produced depraved sinners....This cleansing of the physical organ so as not to pass on disease... was a picture of the deep need for cleansing from depravity, which is most clearly revealed by procreation, as men produce sinners and only sinners. Circumcision points to the fact that cleansing is needed at the very core of a human being, a cleansing God offers to the faithful and penitent through the sacrifice of Christ to come. (MacArthur, J. J. The MacArthur Study Bible. Nashville: Word Pub) (Bolding added)

Circumcision was God’s appointed “sign of the covenant” (Ge 17:11), which signified Abraham’s covenanted commitment to the Lord—that the Lord alone would be his God, whom he would trust and serve. It symbolized a self-maledictory oath (analogous to the oath to which God had submitted himself; see Ge 15:17): “If I am not loyal in faith and obedience to the Lord, may the sword of the Lord cut off me and my offspring (Ge 17:14) as I have cut off my foreskin.” Thus Abraham was to place himself under the rule of the Lord as his King, consecrating himself, his offspring and all he possessed to the service of the Lord. (NIV Study Bible. Zondervan)

Leviticus 26:41 I also was acting with hostility against them, to bring them into the land of their enemies-- or if their uncircumcised heart becomes humbled so that they then make amends for their iniquity, 42 then (Don't miss these critical expressions of time in your Bible reading!) I will remember My covenant with Jacob, and I will remember also My covenant with Isaac, and My covenant with Abraham as well, and I will remember the land.

Leviticus 26 deals with obedience (Lev 26:1-13) and disobedience (Lev 26:14-46, cp similar sections outlining first the blessings for obedience and then the cursings for disobedience = Dt 7:12-26, 28:1-68, 30:1-20) to the Old Covenant of the Law into which Israel had entered at Mt Sinai (Ex 24:3, 6,7, 8). In the last half of Leviticus 26 (Lev 26:14-46) God is reviewing their disobedience and explains that the root of their disobedience is their "hard" uncircumcised heart condition. In other words they were disobedient because they were not genuinely saved (like Abraham Ge 15:6). As an aside, while most of Israel in the OT was not genuinely saved, God always preserved a remnant of genuine believers in every age (see study on the doctrine of the remnant).

Arnold Fruchtenbaum, a Jewish believer, alludes to the concept of remnant commenting that: God chose Israel to be an elect nation, not true of any other nation in this world. However, national election does not guarantee the salvation of every individual member of that nation. Individual salvation is based on individual election on God’s part and faith on man’s part. In Dt 10:16 (see below), individual members of the elect nation are encouraged to ‘circumcise therefore the foreskin of your heart.’ Whereas circumcision of the flesh is a sign of one’s membership in the elect nation (Ed: Fruchtenbaum is not completely correct - This is unfortunately what physical circumcision came to mean, but originally that was not the meaning. It was originally intended to signify that an individual had entered the Abrahamic Covenant by grace through faith and was a mark that they were genuinely saved. The analogy is modern Baptism - water baptism does not save anyone, but does serve as a public testimony that one has been saved), circumcision of the heart is a sign of individual election. (Bolding added)

Deuteronomy 10:16-17 "Circumcise then your heart, and stiffen your neck no more." 17 For the LORD your God is the God of gods and the Lord of lords (Rev 19:16-note), the great, the mighty, and the awesome God who does not show partiality, nor take a bribe.

Physical circumcision was important as the sign of the covenant (cf. Gen. 17:10 and Gen. 17:9, note), and was intended as an outward act bearing eloquent witness to the cutting away of the hardness of sin from the heart of man (cf. Jer. 6:10; Ex. 6:12). (Criswell, W A. Believer's Study Bible: New King James Version. 1991. Thomas Nelson)

Comment: Physical circumcision was originally intended by God to be a sign that one had entered into the Abrahamic covenant (Ge 17:9, 10). In other words, physical circumcision was an outward act which testified that the individual had experienced an inner "circumcision" of their heart. While God is calling on Israel to "circumcise" their hearts, clearly no human being can carry out such an act without supernatural intervention. As the new ESV Study Bible says that "Circumcision of the heart comes from renewal through the Spirit of Christ." God's charge is not just for Israel to "get a grip" and change their rebellious attitude toward Him! Our hearts are intractably deceitful and sick (Jer 17:9) and we are all by nature, hard hearted, stiff necked rebels toward God and His Word, unless and until He graciously brings about an individual's "heart circumcision" in response to that individual's faith - in other words, "spiritual circumcision" is by grace through faith, which sounds like salvation in the NT, because it is!

Dave Guzik: God command them to do something that only He could do in them to show them the need to have the inner transformation, and to compel them to seek Him for this inner work.

Warren Wiersbe comments on Israel's misinterpretation of the rite of circumcision: Unfortunately, this same spiritual blindness is with us today, for many people believe that baptism, confirmation, church membership, or participation in the Lord’s Supper automatically guarantees their salvation. As meaningful as those things are, the Christian’s assurance and seal of salvation isn’t a physical ceremony but a spiritual work of the Holy Spirit in the heart (Php 3:1-10; Col. 2:9, 10, 11, 12). Jewish circumcision removed but a small part of the flesh, but the Holy Spirit has put off the whole “body of the sins of the flesh” and made us new creatures in Christ (Col 2:11). (Be Equipped: Chariot Victor Pub)

Bible Knowledge Commentary: The proper response to their election by the sovereign Lord was to circumcise their hearts (cf. Dt 30:6). An uncircumcised heart means a will that is hardened against God’s commands. It is another way of saying the person is stiff-necked or stubborn (cf. Dt 9:6KJV, Dt 9:13KJV; Dt 31:27KJV). Thus the command to circumcise their hearts assumes that human hearts are naturally rebellious and need correction. Though human hearts are slow to change, Moses warned the nation that no bribe or anything less than an inward transformation could satisfy the Lord, who is the great God. God’s treatment of the helpless (the fatherless . . . the widow, and the alien) further illustrates His absolutely just character (showing no partiality) and highlights His requirement for Israel to be just. (The Bible knowledge commentary) (Bolding added)

Deuteronomy 30:1-6 "So it shall be when all of these things have come upon you (Ed: The prophecy described in the following passages will ultimately be fulfilled at the end of the "time of Jacob's distress" [Jer 30:7], the 3.5 year period which Jesus referred to as the Great Tribulation), the blessing and the curse which I have set before you, and you call them to mind in all nations where the LORD your God has banished you, 2 and you return to the LORD your God and obey Him with all your heart (Ed: Not legalistic obedience, but supernatural obedience motivated by love and desire to be pleasing to the Lord) and soul according to all that I command you today, you and your sons, 3 then the LORD your God will restore you from captivity, and have compassion on you, and will gather you again from all the peoples where the LORD your God has scattered you. 4 "If your outcasts are at the ends of the earth, from there the LORD your God will gather you, and from there He will bring you back. 5 "And the LORD your God will bring you into the land which your fathers possessed, and you shall possess it; and He will prosper you and multiply you more than your fathers. 6 Moreover the LORD your God will circumcise your heart and the heart of your descendants, to love the LORD your God with all your heart and with all your soul, in order that you may live.

(Deut 30:1-5 prophesies of) The gathering of Jews out of all the countries of the earth (that) will follow Israel’s final redemption. Restoration to the Land will be in fulfillment of the promise of the covenant given to Abraham (see Ge 12:7; 13:15; 15:18, 19, 20, 21; 17:8) and so often reiterated by Moses and the prophets. (Circumcision of their heart is a) work of God in the innermost being of the individual is the true salvation that grants a new will to obey Him in place of the former spiritual insensitivity and stubbornness (cf. Jer. 4:4; 9:25; Ro 2:28, 29). This new heart will allow the Israelite to love the Lord wholeheartedly, and is the essential feature of the New Covenant. (MacArthur, J. J. The MacArthur Study Bible. Nashville: Word Pub) (Bolding added)

Bible Knowledge Commentary: The promise that the Lord your God will circumcise your hearts (cf. Dt 10:16) means that God will graciously grant the nation a new will to obey Him in place of their former spiritual insensitivity and stubbornness. After returning to the Promised Land with a new heart they will remain committed to the Lord and therefore will experience abundant blessing (live). Loving Him wholeheartedly (cf. Dt 30:16, 20; see Dt 6:5), they would not fall back into apostasy as they had done before. A new heart is an essential feature of the New Covenant (cf. Ezek. 36:24, 25, 26, 27, 28, 29, 30, 31, 32-see notes), which will not be fulfilled for Israel as a nation until the return of Jesus Christ (cf. Jer. 31:31, 32, 33, 34). (The Bible knowledge commentary) (Bolding added)

Jeremiah 4:4 "Circumcise yourselves to the LORD and remove the foreskins of your heart, men of Judah and inhabitants of Jerusalem, lest My wrath go forth like fire and burn with none to quench it, because of the evil of your deeds."

Here the meaning of circumcision is the idea of purifying, separating from the sinful tendency of the flesh, that propensity inherited from Adam in which the unregenerate seeks only to please self, never God. In other words, God desires that the inward condition match one's outward profession, which pf course is not just an OT idea related to circumcision. God's intent has always been that the outward symbols (e.g., circumcision, baptism) should be signs of an inward reality of a new heart willing to and now able to obey Him. Mere outward conformity to the standards of the covenant does not please God

John MacArthur writes -  This surgery (Ge 17:10, 11, 12, 13, 14) was to cut away flesh that could hold disease in its folds and could pass the disease on to wives. It was important for the preservation of God’s people physically. But it was also a symbol of the need for the heart to be cleansed from sin’s deadly disease. The really essential surgery needed to happen on the inside, where God calls for taking away fleshly things that keep the heart from being spiritually devoted to Him and from true faith in Him and His will. Jeremiah later expanded on this theme (Jeremiah 31:31, 32, 33, 34; cf. Deut. 10:16; 30:6; Ro 2:29). God selected the reproductive organ as the location of the symbol for man’s need of cleansing for sin, because it is the instrument most indicative of his depravity, since by it he reproduces generations of sinners. (The MacArthur Study Bible)(Bolding added)

Jeremiah 9:25 "Behold, the days are coming," declares the LORD, "that I will punish all who are circumcised and yet uncircumcised (now he lists several examples of ancient nations that practiced circumcision and to Judah's dismay placed her right in the middle of the loathed Gentiles!)--26 Egypt, and Judah, and Edom, and the sons of Ammon, and Moab, and all those inhabiting the desert who clip the hair on their temples; for all the nations are uncircumcised, and all the house of Israel are uncircumcised of heart."

Conformity to the external standard of circumcision must be accompanied by "circumcision" of the heart to please God. To see how one can "circumcise the heart" see the teaching by Paul in Romans 2 and Colossians 2 (below).

Bible Knowledge Commentary - If personal achievement or ability would not please God (Jer 9:23), neither would outward conformity to religious rituals. God would punish those circumcised only in the flesh whether they were near or far (Ed: near = Jew; far = Gentile). Judah’s faith in her covenant sign (Ed: cp Ge 17:11) was a misplaced faith because people in some other nations also practiced this ritual-and they were not under God’s covenant. Judah’s actions exposed the fact that the nation was really uncircumcised of heart (cf. Jer 4:4).

Ezekiel 44:6-9 (context Ezek 44:4-5 - "the glory of the LORD filled the" Temple) "And you shall say to the rebellious ones, to the house of Israel, 'Thus says the Lord GOD, "Enough of all your abominations, O house of Israel, 7 when you brought in foreigners, uncircumcised in heart (lacking spiritual circumcision, not regenerate, lacking a new heart) and uncircumcised in flesh, (physical circumcision) to be in My sanctuary to profane it, even My house (the Temple in Jerusalem), when you offered My food, the fat and the blood; for they made My covenant void (speaking of the Old Covenant, the Mosaic Covenant)-- this in addition to all your abominations. 8 "And you have not kept charge of My holy things yourselves, but you have set foreigners to keep charge of My sanctuary." 9 'Thus says the Lord GOD, "No foreigner, uncircumcised in heart and uncircumcised in flesh, of all the foreigners who are among the sons of Israel, shall enter My sanctuary.

Comment: Foreigners refers to Gentiles and not only were they uncircumcised in flesh (physically), they were also uncircumcised in their heart (spiritually). In short they were not regenerate individuals. Apparently at some time in the past Jews had brought Gentiles into the Holy Temple which was against the Mosaic law (they made My covenant void) and the result was that the Temple had been profaned by their presence. 

John MacArthur - Since the Lord’s glory fills the temple, it is sanctified (Ezek 44:4), and God is particular about what kind of people worship there. Sins of the past, as in Ezekiel 8:1-11:25, must not be repeated and if they are, will exclude their perpetrators from the temple. Only the circumcised in heart may enter (Dt 30:6; Jer 4:4; Ro 2:25-29), whether of Israel or another nation (Ezek 44:7, 9). Many other peoples than Jews will go into the kingdom in unresurrected bodies, because they have believed in Jesus Christ and were ready for His coming. They will escape His deadly judgment and populate and reproduce in the 1,000 year kingdom (Ed: The Judgment of the Sheep and Goats identifies Gentile believers who will enter into the Millennial Kingdom; see "Who populates the Millennial Kingdom?"). Such circumcision pertains to a heart which is sincere about removing sin and being devoted to the Lord (cf. Jer 29:13). In the Millennium, a Jew with an uncircumcised heart will be considered a foreigner (Ezek 44:9). “Uncircumcised in flesh” refers to sinners and “foreigners” identifies rejecters of the true God. (MacArthur Study Bible)

Acts 7:51  "You men who are stiff-necked and uncircumcised in heart and ears are always resisting the Holy Spirit; you are doing just as your fathers did.

STIFF-NECKED (Ex 32:9 33:3,5 34:9 Dt 9:6,13 31:27, 2Chr 30:8, Neh 9:16, Ps 78:8, Isa 48:4 Jer 17:23)

Stephen, the accused, is now the accuser, and the situation becomes intolerable to the Sanhedrin.  

Furneaux: "And as he saw his countrymen repeating the old mistake--clinging to the present and the material, while God was calling them to higher spiritual levels--and still, as ever, resisting the Holy Spirit, treating the Messiah as the patriarchs had treated Joseph, and the Hebrews Moses--the pity of it overwhelmed him, and his mingled grief and indignation broke out in words of fire, such as burned of old on the lips of the prophets" 

Stiff-necked (4644)(Sklerotrachelos from skleros + tráchelos = the neck) is found only in Acts 7:51 (but see 6 uses in Lxx below) and is literally stiff–necked which is figuratively describes someone as obstinate, which in turn is defined as one who manifests a fixed and unyielding course or purpose implying usually an unreasonable persistence. This is one who is perversely adhering to an opinion, purpose, or course in spite of reason, arguments, or persuasion. Stephen is saying in essence that the Jews would not allow themselves to be persuaded by the Truth of the Gospel, which had been proclaimed throughout the Old Testament (see Gal 3:8) and was the proclamation the Holy Spirit would have used to circumcise their hearts if they had received it in faith instead of pursuing their own righteousness by works of the law (rather than by grace).  

Sklerotrachelos portrays the idea of a stubborn ox that cannot be broken; and a neck so strong the animal is useless, because it cannot be turned right or left.

Sklerotrachelos - 5 verses in the Septuagint.

Exodus 33:3 "Go up to a land flowing with milk and honey; for I will not go up in your midst, because you are an obstinate (Lxx = sklerotrachelos) people, and I might destroy you on the way."  5 For the LORD had said to Moses, "Say to the sons of Israel, 'You are an obstinate  (Lxx = sklerotrachelos) people; should I go up in your midst for one moment, I would destroy you. Now therefore, put off your ornaments from you, that I may know what I shall do with you.'"

Exodus 34:9 He said, "If now I have found favor in Your sight, O Lord, I pray, let the Lord go along in our midst, even though the people are so obstinate, and pardon our iniquity and our sin, and take us as Your own possession."

Deuteronomy 9:6 "Know, then, it is not because of your righteousness that the LORD your God is giving you this good land to possess, for you are a stubborn people....13  "The LORD spoke further to me, saying, 'I have seen this people, and indeed, it is a stubborn people.

Proverbs 29:1 A man who hardens his neck after much reproof Will suddenly be broken beyond remedy.

Sklerotrachelos is first in the Greek sentence for emphasis. In Acts 7:1-60 This is the climax of Stephen’s speech (Acts 7:51-53), the personal application that cut his hearers to the heart. Throughout the centuries, Israel had refused to submit to God and obey the truth He had revealed to them (including the Gospel, albeit as far as we can determine not as in a full-orbed sense as we have it explained in the New Testament). Their ears did not hear the truth, their hearts did not receive the truth, and their necks did not bow to the truth. As a result, they killed their own Messiah and then proceeded to kill Stephen.

UNCIRCUMCISED IN HEART - They had only physical circumcision which was useless in regard to attaining righteousness before God. The Jews placed great stress on the physical ritual of circumcision, forgetting that it was meant to be symbolic of their complete dedication to the will and purposes of God. Thus, their hearts were still cold toward God and their ears inattentive to His Word, so that God could not reach them

HEART AND EARS - "The phrase “uncircumcised hearts and ears” is another figure for stubbornness." (NET Note)

Uncircumcised (564)(aperitmetos from a = negates + peritemno = to cut around, to circumcise) is an adjective which literally describes that which is not cut around. In context it is used figuratively of those uncircumcised in heart and ears a spiritual condition which resulted in their stubbornness toward God and His Messiah. In Jeremiah 9:25 the Lxx uses aperitmetos figuratively to refer to gentiles with uncircumcised foreskin. 

ARE ALWAYS RESISTING THE HOLY SPIRIT (Ne 9:30):

Isaiah writes "But they rebelled and grieved His Holy Spirit; Therefore, He (Jehovah) turned Himself to become their enemy, He fought against them." (Isaiah 63:10)

Resisting is literally rushing against or upon in a hostile manner. 

John Phillips explains that "There are three ways in which the Holy Spirit can be opposed. He can be grieved, He can be quenched, and He can be resisted. Only a Spirit-indwelt believer can grieve the Holy Spirit. The word grieve is a love-word. We can grieve only someone who loves us and who stands in a special relationship to us. A church can quench the Holy Spirit by allowing men to usurp His authority, by refusing to follow His leading, or by permitting false doctrine or moral evil to take root. Sinners resist the Holy Spirit. Stephen now dropped his defense and went boldly to the attack, vilifying his listeners for their persistent and continuing opposition to God. Their chief sin was that of resisting the Holy Spirit. Their treatment of the saviors, the Scriptures, and the sanctuaries God had given them, and, above all, their treatment of the Son of God, constituted a persistent sin against the Holy Ghost." (Explore Acts)

Resisting (496)(antipipto from antí = against + pípto = fall) strictly, fall against, rush against; hence, strive against, oppose: resist by actively opposing pressure or power. To resist by force and violence. The picture is of men who were continually (present tense) rejecting the Holy Spirit’s appointed messengers and their Gospel proclamation. (CompareJesus’ sermon in Mt 23:13–39).

Griffis writes that "The Greek word here is antipipto, which means "to pull against," like a heifer that pulls backward."  (Characters with Character)

Antipipto 3v in Lxx: 

Exodus 26:5 "You shall make fifty loops in the one curtain, and you shall make fifty loops on the edge of the curtain that is in the second set; the loops shall be opposite each other.... 17 "There shall be two tenons for each board, fitted (Antipipto - conveys idea opposite one to the other) to one another; thus you shall do for all the boards of the tabernacle.

Numbers 27:14 for (What is "for" explaining? See context - Nu 27:12-13 - explains why Moses can only see the Promised Land but cannot enter) in the wilderness of Zin, during the strife of the congregation, you (Moses)  rebelled (Lxx = Marah = was contentious, disobedient; Lxx = antipipto) against My command to treat Me as holy before their eyes at the water." (These are the waters of Meribah of Kadesh in the wilderness of Zin.)

The English translation of the Septuagint of Nu 27:14 =  because you transgressed my word in the wilderness of Sin, when the congregation resisted to sanctify me. You did not sanctify me at the water before them.” (This is water of dispute of Kades in the wilderness of Sin.) 

Net Note explains it this way - Using the basic meaning of the word qadash, "to be separate, distinct, set apart", we can understand better what Moses failed to do. He was supposed to have acted in a way that would have shown God to be distinct, different, holy. Instead, he gave the impression that God was capricious and hostile – very human. The leader has to be aware of what image he is conveying to the people. 

YOU ARE DOING JUST AS YOUR FATHERS DID (cp Heb 3:12, 8, 4:2, cp Jesus Mt 23:31): Literally "as your fathers also ye."  Their fathers had made "external worship" a substitute for spiritual obedience. Stephen's piercing denunciation of his Jewish audience reminds us of similar words of Jesus in Luke 11:47-51. 

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