FINALLY THEN, BRETHREN, WE REQUEST AND EXHORT YOU IN THE LORD JESUS: Loipon oun, adelphoi, erotomen (1PPAI) humas kai parakaloumen (1PPAI) en kurio Iesou: (1Thes 2:11; Ro 12:1; 2Corinthians 6:1; 10:1; Ephesians 4:1; Philemon 1:9,10; Hebrews 13:22) (1Thes 4:2; Ephesians 4:20; 2Thessalonians 2:1; 1Timothy 5:21; 6:13,14; 2Timothy 4:1)

1 Thessalonians 4 can be divided as follows...

1 Thes 4:1-2     = General Call to a God Pleasing Walk
1 Thes 4:3-12   = Specific Aspects of God Pleasing Walk

1 Thes 4:3-8   = Sanctification in Area of Sexual Purity
1 Thes 4:9-12 = Sanctification in Area of Love and Work

1 Thes 4:13-18 = Hope for Grieving Saints

Paul now introduces the practical hortatory (exhortational) section (refer to chart above), much like he does in other epistles...

I urge (parakaleo) you therefore, brethren, by the mercies of God, to present your bodies a living and holy sacrifice, acceptable to God, which is your spiritual service of worship. (see note Romans 12:1)

I, therefore, the prisoner of the Lord, entreat (parakaleo) you to walk in a manner worthy of the calling with which you have been called (see note Ephesians 4:1)

Notice that in the first 2 verses (1 Thes 4:1, 2) Paul is quite general but that in the next section (1 Thes 4:3, 4, 5, 6, 7, 8) he is very specific as he deals with sexual purity.

Hiebert makes an excellent point noting that...

It is instructive to notice that the teaching concerning the second advent (see Second Coming) is preceded and followed by sections dealing with daily life and conduct. Although the teaching concerning the Lord's return was clearly an exciting subject for the Thessalonians, Paul endeavored to set it into a context of practical daily living. The Christian's hope for the future must have a sanctifying influence upon the present. (Hiebert, D. Edmond: 1 & 2 Thessalonians: BMH Book. 1996)

Finally (3062)(loipon from loipós = remaining) pertains to the part of a whole which remains or continues and thus constitutes the rest of the whole. Finally is not the most satisfactory rendering since it commonly implies that the conclusion is next. A better translation would be "for the rest," or "further." In fact literally this phrase is as for the rest and in every case, the use of this Greek expression has the idea of something left over. That is, all that remains is to offer these exhortations and instructions.

Paul uses loipon frequently in the concluding portion of his Epistles, introducing practical exhortations but not necessarily implying that the letter is drawing to a close. In other words, the "finally" formula is often used by Paul to attach in a somewhat loose way (even in the midst of an Epistle) a new subject to the one which he has been discussing. In the present letter he is marking a transition in the subject matter (see table above), similar to his practice in other epistles such as in

Philippians 3:1 Finally my brethren rejoice..." see note

2 Thessalonians 3:1 Finally, brethren, pray for us...

2Corinthians 13:11 Finally, brethren, rejoice, be made complete, be comforted, be like-minded, live in peace; and the God of love and peace shall be with you

As previously noted, Satan had seemingly won the battle by successfully hindering Paul from speaking face to face to these relatively young (in the faith) saints in Thessalonica (1 Thes 2:17; 2:18 see notes 1Th 2:17; 18). And yet what Satan meant for evil, the sovereign, omnipotent Creator used for good (cf Romans 8:28-note, Ge 50:20), the Spirit inspiring Paul to take up and write this precious epistle that has ministered to scores of believers throughout the ages!

Then (3767) (oun) means therefore, so, consequently and introduces a logical result or inference from that which has previously been stated.  Paul had just prayed for the establishment of their hearts unblamable in holiness before God at the coming of the Lord Jesus (see note 1 Thessalonians 3:13) and therefore now exhorts them to the same end because he knew that the highway to holiness is only along the path of obedience to the revealed will of God.

Brethren (80) (adelphos from collative a = copulative prefix {joining together coordinate words} or connective particle serving to join or unite + delphús = womb) is literally one born from same womb and is literally the word for a male having the same father and mother. Figuratively, as used in this verse adelphos refers to Paul's fellow believers in Thessalonica which includes not just brothers but sisters in Christ, all of whom are united by a bond of affection, for all have been born of one Spirit and have God as their Father and Jesus as their Brother. In sum, Paul appeals to the Thessalonians by affectionately referring to them as his brothers in Christ.

Hiebert reminds us that...

The readers are again affectionately addressed as "brothers." These appeals are being made in the interest of that spiritual brotherhood in Christ into which they have been brought. It is a loving reminder of their common interests and concerns as Christians. (Ibid)

Request and exhort - The combination of two verbs expresses the writer’s sense of the paramount importance of maintaining the Christian character. The two verbs enforce each other and add emphasis to the request being made. Having prayed for their establishment in holiness, Paul now exhorts and instructs them to that end. The prayer that they may be blameless in holiness at the Lord's return cannot be realized without the cooperation of those for whom the prayer is made. Paul therefore urges his beloved converts to excel in their striving after a holy walk.

Request (2065)(erotao from éromai = ask, inquire) means to ask for, usually w implication of an underlying question. Erotao provides the most delicate and tender expression for prayer or request with the one asking and the one being asked being on an equal level, such as the Lord Jesus asking of the Father (it is never used of men asking God for we are not on the same level as the Son is to the Father). In the present context Paul is speaking to the believers at Thessalonica as a fellow believer and not as someone who is "holier than though" as we often say. Paul is calling for them to seriously strive to walk holy, worthy and without blame.

Note that both erotao and parakaleo are in the present tense indicating that these are meant to convey continuous action -- we are continually requesting and continually exhorting you.

Paul has similar uses of erotao in the following passages...

But we request (erotao) of you, brethren, that you appreciate those who diligently labor among you, and have charge over you in the Lord and give you instruction, (note 1 Thessalonians 5:12)

Now we request (erotao) you, brethren, with regard to the coming of our Lord Jesus Christ, and our gathering together to Him, (2 Thessalonians 2:1)

Indeed, true comrade, I ask (erotao) you also to help these women who have shared my struggle in the cause of the gospel, together with Clement also, and the rest of my fellow workers, whose names are in the book of life. (note Philippians 4:3)

Exhort (3870)(parakaleo from para = side of + kaléo = call) conveys the basic idea of calling one alongside to assist, help or give aid.  Its primary meaning in the NT is the urging of someone to do something, more specifically some ethical course of action. Because a person can be called alongside for many purposes, parakaleo has a wide range of meanings as determined by the context, these meanings including to entreat, to appeal to, to summon, to comfort, to exhort, or to encourage.

Despite the fact that parakaleo can convey a wide range of meanings most Bible versions translate this verb with either exhort or urge.

In English exhort (from Latin exhortari from ex- = thoroughly + hortari = to excite, encourage, urge) means  to urge or persuade someone earnestly; advise strongly. To give warnings or advice. To make urgent appeals.

In English to urge (from Latin urgere = to press or drive) means to strongly recommend, to entreat earnestly to do something, to encourage someone to continue. To advocate or recommend earnestly and persistently; plead or insist. To press or impel to action, effort, or speed. Synonyms include egg (on), exhort, goad, prick, prod, prompt, propel, sic, spur.

In classic Greek parakaleo was used to exhort troops about to go into battle which is apropos as Paul proceeds in the following verses with a call to sexual purity! No one reading this has ever "battled" with this enemy I'm sure! I'm being sarcastic.

Always at the root meaning of parakaleo is the idea of enabling a person to meet a difficult situation with confidence and with gallantry.

A Greek historian recorded the struggle of a military regiment which had lost heart and was utterly dejected. The general sent a leader to come alongside these downcast troops in such a way that their courage was reborn and a body of dispirited men became fit for heroic action! So if you have been defeated in the area of sexual purity, don't give up but allow the apostle's timeless words come alongside your spirit and lift you up to fight the good fight of faith.

In the Lord Jesus - In His name, and by His authority. The point is clear that this is God's will and not just Paul's view on sexual purity.

Bruce explains that in the Lord Jesus implies...

not only his authority (which is indicated by dia = through or by in verse 2) but “a sense that Christ is thoroughly involved in the situation or action in question—a consciousness of Christ”...The writers, being themselves “in the Lord Jesus,” are counseling fellow-members of Christ. (Bruce, F F: 1 and 2 Thessalonians. Word Biblical Commentary. Dallas: Word, Incorporated. 1982 or Logos)

Hiebert adds that in the Lord Jesus...

indicates that the activity being engaged in is carried on in virtue of their union with the Lord Jesus, not "by the Lord Jesus" (KJV and Phillips). It is not a form of adjuration. The phrase sets out the spiritual context for the following exhortations. They are united in Him as their common Lord. Paul's appeal carries authority for them because it operates in the sphere of the regenerate life. He does not presume to advise them on the basis of personal status or special ecclesiastical prerogatives, but because writers and readers are members of one family, the Body of Christ. (Hiebert, D. Edmond: 1 & 2 Thessalonians: BMH Book. 1996)

Vine comments that...

in the original the order is “we beseech you, and we exhort in the Lord Jesus”; thus the name of the Lord is directly associated only with the word “exhort.” Paul begs on his own account, as one who loved them, but he urges in the name of his Lord and theirs, cp. 2Thessalonians 3:12. What he laid on the consciences of the saints did not originate with himself but with the Lord, to whose authority, therefore, he appealed. For a good illustration see Matthew 8:9. (Vine, W. Collected writings of W. E. Vine. Nashville: Thomas Nelson or Logos)

THAT, AS YOU RECEIVED FROM US INSTRUCTION AS TO HOW YOU OUGHT TO WALK AND PLEASE GOD: hina kathos parelabete (2PAAI) par' hemon to pos dei (3SPAI) humas peripatein (PAN) kai areskein (PAN) theo: (1Thes 4:11,12; Acts 20:27; 1Corinthians 11:23; 15:1; Philippians 1:27; Colossians 2:6; 2Thessalonians 3:10-12) (1Thes 2:12) (Romans 8:8; 12:2; Ephesians 5:17; Colossians 1:10; Hebrews 11:6; 13:16; 1John 3:22)

As you received - Paul is reminding them of instructions he had given them on his first visit. He is not asking them to do something new. Note that the word instruction is not in the Greek but is supplied by the translators. Paul had used the same verb paralambano in reference to the initial presentation of the gospel to the Thessalonians (see 1Th 2:13-note). As discussed in preceding sections, the missionaries had not only declared the way of salvation to the Gentiles but they had also discipled these young converts, instructing them in how to live so as to please God. Now Paul reaffirms this teaching before he proceeds to supplement it. These passages help us understand what Paul meant when he wrote that...

we (he, Silas and Timothy) night and day keep praying most earnestly that we may see your face, and may complete what is lacking in your faith? (see note 1 Thessalonians 3:10)

What was lacking in their faith constitutes the instructions and exhortations found in chapters 4 and 5 (and also probably includes the subjects addressed in the second letter).

Received (3880)(paralambano from para = beside + lambano = appropriate, receive) means to receive from another, to receive alongside or to take to oneself (into close association). There are two basic ideas - to take or to receive.

Paralambano lays stress not so much on the manner of the Thessalonians’ receiving, as on the contents of what they received.

Here paralambano is used for the reception of something transmitted, specifically spiritual instruction or truth. The aorist tense looks back to the time when the Thessalonians heard the missionaries' proclaim the gospel and records their active response to that message - they took hold of the divine message. They received it alongside. They took it to themselves.

Paralambano conveys the idea that they had received the word of God's message into their mind and were taught and so they learned it. Paralambano also has nuances of seizing or taking to one's self or taking something into one's possession (ponder that as you think about the "attitude" of the Thessalonians. How do I compare when I am confronted with "the word of God's message"?)

Similar uses of paralambano as it relates to the reception of truth are found in...

How -  Christians should have some know how. They should know how to gain victory over sin in their lives. (Richison)

Keathley concludes that the missionaries had...

laid a doctrinal foundation and then taught them the moral obligations of that doctrine. This was Paul’s practice and forms a precedent for us: first doctrine, then duty; precept and then practice. Doctrine should lead to godly practice, but a godly practice that is in keeping with God’s Word as to its character and the means (root to fruit). Learning to live and please God is a matter of biblical instruction. It is neither natural nor innate. Without the Word, there is simply no way any of us are going to be able to walk as we should so we are able to please the Lord (see Col 2:6-note). Over and over again in the Old Testament we read that God’s people are to walk in His ways, statutes, and laws, i.e., according to the Word (Lev 26:3; Deut 5:33; 8:6; 10:12; Josh 22:5). (See discussion of 1 Thessalonians 4:1-12)

Walk (4043) (peripateo from peri = about, around + pateo = walk, tread) means literally to go here and there in walking, to tread all around. Most NT uses are figurative and refer to one's manner of life, one's moral conduct or one's life-style. Life is often represented as a journey.

The NIV renders 1 Thes 4:1 "how to live in order to please God". Indeed to walk in a manner that pleases God should be the ultimate goal and aim every Christian's walk (cp Col 1:1-note, Col 3:20-note Pr 16:7 Php 4:18-note 2Ti 2:4-note Heb 11:5-note, Heb 13:16-note 1Jn 3:22 ).

Luke uses peripateo to describe Zacharias and Elizabeth, the parents of John the Baptist, as being