FOR YOU YOURSELVES KNOW, BRETHREN: Autoi gar oidate, (2PRAI) adelphoi:

For (1063)(gar) is a conjunction basically introducing an explanation and here opens this section marking the transition from Paul's primary thanksgiving for his assurance of the authenticity of their conversion (1Thes 1:2-10) to the body or  of the letter (1Thes 2:1-5:22).

What the for  links back to is debatable. Some feel that the fact that Paul begins with our coming indicates that he is linking this back to the related subject in 1Thessalonians 1:9 (note) what kind of reception we had with you.

Ryrie on the other hand feels that...

This verse builds on 1Thes 1:5. not in vain = not without results. Paul returns to this subject in 1Thes 2:13, after reviewing his ministry (1Thes 1:1-12). (The Ryrie Study Bible: New American Standard Translation: 1995. Moody Publishers)

Hiebert agrees writing that...

The conjunction for (gar), not represented in the NIV rendering, is usually used to link a statement with what has immediately preceded, but here it obviously does not substantiate the reference to Christ's deliverance from coming wrath (note 1Thessalonians 1:10). Clearly the connecting link is broader and finds its proper explanation "in the train of thought which was running in the Apostle's mind."'

Best agrees that "for" links back "to the whole of 1Thes 1.2-10 with special reference to 1Thessalonians 1:5 where the entrance of Paul was discussed."' Thus Paul here takes up explicitly the defense already hinted at in 1Thessalonians 1:5. This entire section is in fact an elaboration of the two points mentioned in 1Thessalonians 1:9.

1Thes 2:1-12 are an expansion of what kind of reception you gave us, whereas 1Thes 2:13-16 renew the theme of how you turned to God from idols to serve the living and true God.

Paul had informed the readers about the reports he was continually receiving concerning the ministry at Thessalonica (note 1Thessalonians 1:9), but the Thessalonians were not dependent on such reports for their knowledge of what happened. (Hiebert, D. Edmond: 1 & 2 Thessalonians: BMH Book. 1996)

MacDonald makes the salient point that...

What we are is far more important than anything we ever say. Our unconscious influence speaks more loudly than our conscious influence. James Denney said:

A Christian’s character is the whole capital he has for carrying on his business. In most other callings, a man may go on, no matter what his character is, provided his balance at the bank is on the right side; but a Christian who has lost his character has lost everything.

The missionary martyr Jim Elliot wrote in his journal:

In spiritual work, if nowhere else, the character of the worker decides the quality of his work. Shelley and Byron may be moral free-lancers and still write good poetry. Wagner may be lecherous and still produce fine music, but it cannot be so in any work for God. Paul could refer to his own character and manner of living for proof of what he was saying to the Thessalonians. Nine times over in this first epistle he says, “You know,” referring to the Thessalonians’ firsthand observation of Paul’s private as well as public life. Paul went to Thessalonica and lived a life that more than illustrated what he preached; it went beyond illustration to convincing proof. No wonder so much work in the Kingdom is shoddy; look at the moral character of the worker. (MacDonald, W & Farstad, A. Believer's Bible Commentary: Thomas Nelson or Logos)

The Disciple's Study Bible has an interesting comment noting that...

Paul outlined his method of evangelism and gave us an example to follow:

he ministered despite hardship and persecution;
he ministered with pure motives;
he ministered the true gospel of Christ;
he ministered for God's glory;
he ministered selflessly;
he ministered in humility;
he ministered with care and sacrificial love;
and he ministered long and laboriously.

Little wonder Paul could say "our visit to you was not a failure'' (v 1). (Disciple's Study Bible)

In this section (1Thes 2:1-12) Paul reminds the Thessalonians of how the missionaries had chosen to minister, live and work while in their presence and in so doing provides them a description of the specific behaviors and attitudes he desired for them to imitate, in so doing also providing a model that is applicable to all believers everywhere. Paul alludes to his desire (in the context of discussing work) for them to imitate his walk in the second epistle, writing that the missionaries worked ...

in order to offer ourselves as a model (see tupos) for you, that you might follow our example. (2Thes 3:9)

For you yourselves know - An appeal again to the Thessalonians own experience (cf. 1Thessalonians 1:5), as distinguished from the report of others, and strengthened in the present instance by the repetition of the significant word brethren. You is emphatic in the Greek emphasizing that the Thessalonians knew personally how Paul’s team came into Thessalonica with the gospel (see notes 1Thessalonians 1:5; 2:1, 2:2, 2:5, 2:11; 4:2).

Know (1492) (oida) refers to having come to a perception or realization of something. Oida generally means to know intuitively or instinctively. To be acquainted with. To have information about. Know occurs repeatedly throughout chapter two, emphasizing that the Thessalonians knew this gospel team intimately. Paul was reminding them of his exemplary witness, not to boast but that they too might walk in a manner worthy of the God Who calls us into His own Kingdom and glory.

Michael Holmes in the NIV Application Commentary (Zondervan) observes that...

The repeated appeal to the Thessalonians’ own knowledge of these two matters (1Thes 2:1-2, 5, 9-11) serves both to minimize the distance between Paul and the Thessalonians and to reinforce the relationship between them — points characteristic of ancient “letters of friendship”

Not only do others report the power and efficacy of our preaching among you, but you yourselves are experimentally acquainted with it as Paul had recorded in chapter 1...

for our gospel did not come to you in word only, but also in power and in the Holy Spirit and with full conviction; just as you know what kind of men we proved to be among you for your sake. (See note 1Thessalonians 1:5)

Brethren (80) (adelphos from collative a = denoting unity + delphús = womb) (used 18x in 1Thessalonians proportionately greater than any other Pauline epistle) is literally one born from same womb and so a male having the same father and mother as reference person. Figuratively, adelphos as in this verse refers to a close associate of a group of persons having well-defined membership, specifically here referring to fellow believers in Christ who are united by the bond of affection.

THAT OUR COMING TO YOU WAS NOT IN VAIN: ten eisodon hemon ten pros humas hoti ou kene gegonen, (3SRAI): (1Thes 2:13; 1:3-10; 2 Thessalonians 3:1 ) (1Thes 3:5; Job 39:16; Psalms 73:13; 127:1; Isaiah 49:4; 65:23; Habakkuk 2:13; 1 Corinthians 15:2,10,58; 2 Corinthians 6:1; Galatians 2:2; 4:11; Philippians 2:16)

The Jerusalem Bible renders it "our visit to you has not proved ineffectual."

Coming (our entering in) (1529) (eisodos from eis = in + hodos = a way) literally means a way in, an entrance. Eisodos can refer to the action of coming in (access, entrance). It is used in the first chapter of entrance upon Gospel work into the locality and/or as the reception given (acceptance or welcome as in 1 Thes 1.9...

For they themselves report about us what kind of a reception (eisodos) we had with you, and how you turned to God from idols to serve a living and true God (see note)

McGee puts it this way...

When he (Paul) came to Thessalonica, it rocked a great many folk, bringing many to a saving knowledge of Christ. And it brought a church into existence. Paul was not simply talking about a theory or a philosophy, but about something that worked in Thessalonica. The gospel walked down the streets of that city, and it got into the hearts and homes and lives of men and women. (McGee, J V: Thru the Bible Commentary:  Thomas Nelson or Logos)

Was not - is more literally "had not come to be" or "that it has not become empty". Literally it reads "that it did not become vain".

Was not (1096) (ginomai)  refers to what has come into existence. Ginomai in perfect tense point to fact that an enduring result was secured, that the effects of Paul and Silas' coming to Thessalonica continued into the present. The perfect tense expresses this as an accomplished, unassailable fact. And this effect continues even into eternity for Paul says later that the Thessalonian believers are his

hope and joy and crown of exultation...in the presence of our Lord Jesus at His coming! (see note 1Thessalonians 2:19)

A T Robertson (Word Pictures) rightly notes that

Every pastor watches wistfully to see what will be the outcome of his work.

Vain (2756) (kenos) means empty, hollow, vain, fruitless, without usefulness or success. Kenos can also refer to that in which there is nothing of truth or reality and which is thus false or fallacious. Kenos can describe one who cannot be depended upon and whose deeds do not correspond to his words.

Paul used kenos again in chapter 3 writing that...

when I could endure it no longer, I also sent to find out about your faith, for fear that the tempter might have tempted you, and our labor would be in vain. (See note 1Thessalonians 3:5)

A similar expression is used by Paul in his letter to the saints at Philippi exhorting them to be continually

holding fast the word of life, so that in the day of Christ I will have reason to glory because I did not run in vain  [kenos] nor toil in vain [kenos] (Philippians 2:16 note)

Both the previous passages refer to laboring to the point of exhaustion, something Paul did not want to be for naught (in vain). It is therefore no coincidence that kenos is used here at the beginning of a section which not only alludes to Paul's tent-making activities (1Thessalonians 2:9 - note), but also the labor and effort of his whole evangelistic work (1Thes 2:2, 2:8).

Robertson (Word Pictures) uses the related word mataios (3152) stating that...

In 1Cor 15:14, 17 Paul speaks of empty the preaching and vain the faith (both vain if the resurrection is not truth). One easily leads to the other...

1Cor 15:14 and if Christ has not been raised, then our preaching is vain (kenos), your faith also is vain.

1Cor 15:17 and if Christ has not been raised, your faith is worthless (mataios); you are still in your sins.

Kenos is often used in speaking of work which is either futile and useless in itself (1Cor 15.58), receives no reward (Mk 12.3; Lu 20.10), or produces no result (1 Cor 15.10).

Paul's coming to the Thessalonians was not empty of real meaning or purpose and was not a failure (in the sense of being ineffective) for they themselves are, in view of their genuine conversion (their "work of faith, labor of love and steadfastness of hope in our Lord Jesus Christ" 1Thessalonians 1:3)  the evidence of the efficacy and success of the Gospel which is the power of God unto salvation (Romans 1:16 - note). Paul and Silas had arrived in Thessalonica which apparently had no believers in Christ (see notes Acts 17:1-9). They left a vibrant, dynamic church that was imitating their example, growing in faith and love, standing steadfast against persecution, and becoming an example to all believers sounding forth the gospel across the world. Their coming with the gospel had resulted in changed lives and so clearly their visit had not been a failure (kenos). The occasion for the writing of this letter in fact was when Paul had learned from Timothy (see note 1Thessalonians 3:6) that the assaults of Satan had not annulled or derailed their labors at Thessalonica.

On the other hand one could also interpret not in vain as a reference to the character and ethic of the missionaries and their work. In other words their approach was not with unsound motives or methods (as described in 1Thes 2:2-12; cf their "exemplary witness"). But while not in vain might refer to the character of their mission and not the results of their labors, in fact it surely true that character cannot be separated from results and thus their sound character produced credible results, so that neither of these were in vain!

Guzik notes that not in vain could refer here...

either to the result of the ministry, or the character of the ministry. Because it was evident to everyone that Paul’s ministry in Thessalonica was a success, it is better to see it as a reference to the character of Paul’s ministry. His coming was not empty or hollow, as if he were a mere salesman or marketer.

Green explains this section noting that...

The Thessalonians knew what kind of persons Paul and the others were (1Thessalonians 1:5b), and this section now helps them to remember in detail the blameless character they exhibited. The call to remember what they already knew appears frequently in this section (1Thess 2:1, 2:2, 2:5, 2:9, 2:10, 2:11) and at other points in this letter (1:5; 3:3, 3:4; 4:2; 5:2; and cf. 2 Thess. 2.5-6; 3.7). In ancient ethical instruction, moralists commonly called their readers to remember what they already knew (e.g., Dio Chrysostom 17.1-6), and Paul repeatedly does the same, bringing to mind not only the teaching he had previously given the church but also helping them recall his character upon his “entry” to the city (see 1Thessalonians 1:9). He reminds the Thessalonians that his entry was not a failure. (Green, G. L. The Letters to the Thessalonians. The Pillar New Testament Commentary. Grand Rapids, Mich.; Leicester, England: W. B. Eerdmans Pub.; Apollos)

Vine has a thoughtful note worth pondering...

Though the apostle well knew that no labor in the Lord is vain, 1 Corinthians 15:58 (Therefore, my beloved brethren, be steadfast, immovable, always abounding in the work of the Lord, knowing that your toil is not in vain in the Lord.), he also knew that only in the day of Christ, when all service is to be reviewed by the Lord, 1 Corinthians 3:12, 15 (Now if any man builds upon the foundation with gold, silver, precious stones, wood, hay, straw...15 If any man's work is burned up, he shall suffer loss; but he himself shall be saved, yet so as through fire.), will it be finally manifest whether or no he had run and labored in vain, Philippians 2:16 (holding fast the word of life, so that in the day of Christ I may have cause to glory because I did not run in vain nor toil in vain.). He earnestly desired, therefore to assure himself of the stability of his work, and such tidings as Timothy had brought comforted and gladdened his heart, 1Thes 3:6-8. (Vine, W. Collected writings of W. E. Vine. Nashville: Thomas Nelson or Logos) (Comment: Dear reader, today would be a good time to ponder your life work. {Download and read John Piper's book Don't Waste Your Life} Is your work "in Christ" {John 15:5} and destined to endure the Refiner's fire and so last throughout eternity (see note Ephesians 2:10)? Or is it "in self" and destined for destruction? Is there some disciple you need to call to see how they are walking in their Christian life?)

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