Blamelessly (274) (amémptōs from the noun ámemptos from a = negates following word + mémphomai = find fault) means irreproachably, faultlessly. The noun describes that which is without defect or blemish and thus describes not being able to find fault in someone or some thing (cf use in He 8:7 {note} regarding the Old Covenant). The idea is that the person is such that he or she is without the possibility of rightful charge being brought against them. Paul and his companions' life before the Thessalonians was such that there was no legitimate ground for accusation. This doesn’t mean that his enemies didn’t accuse him—because they did—but the charges didn’t stick. The only other NT use of the adverb amémptōs is in chapter 5, Now may the God of peace Himself sanctify you entirely; and may your spirit and soul and body be preserved complete, without blame (blamelessly) at the coming of our Lord Jesus Christ. (see note 1Thessalonians 5:23) McGee makes a good point... People will say ugly things about you, but the important thing is to make sure the criticisms are not true. Paul and his companions maintained a holy life. A holy life does count. It has nothing to do with obtaining your salvation, but it has everything to do with the salvation of folk around you, because they are watching you. (McGee, J V: Thru the Bible Commentary: Thomas Nelson or Logos) Although Paul used a different word, his prayer in the next chapter for the Thessalonian saints was that... He may establish your hearts unblamable (amomos) in holiness before our God and Father at the coming of our Lord Jesus with all His saints. (see note 1Thessalonians 3:13) This adjective ámemptos was often used to characterize someone who is flawless in the sight of other people. The adverb amémptōs (differs by mark over the "o") is the very word archeologists have found on Christian tombs from ancient Thessalonica. When people wanted to identify a deceased friend or loved one as a Christian, they inscribed "amémptōs" or "blameless" on his or her grave, such behavioral blamelessness (not just the imputed and forensic) is the Lord’s desire for His church. In secular Greek it was used in the Greco-Roman world of people of extraordinary civic consciousness. Barclay adds that ámemptos... expresses what the Christian is to the world. His life is of such purity that none can find anything in it with which to find fault. It is often said in courts of law that the proceedings must not only be just but must be seen to be just. The Christian must not only be pure, but the purity of his life must be seen by all. (Barclay, W: The Daily Study Bible Series, Rev. ed. Philadelphia: The Westminster Press) Paul, Silvanus and Timothy had behaved in such a manner that they had not elicited any reproach from the Thessalonians regarding their character. Even if a charge had been made against them, the adverb amémptōs signifies that the charge could not have been substantiated! Beloved, could other believers say that you have lived devoutly, uprightly and blamelessly before them? Hiebert says that blamelessly sums up their character writing that... It claims an irreproachable conduct as a whole, indicating that no charges can be maintained, whatever charges might be made against someone. It "affixes the seal of approval both by God and man.' The lives of the messengers had demonstrated that they not only believed the gospel but also behaved it. They were deeply aware of the importance of living lives that commended the gospel if their preaching was to have abiding results. They had conducted themselves with the utmost fidelity in word and deed toward the readers—you who believed (Hiebert, D. Edmond: 1 & 2 Thessalonians: BMH Book. 1996) You believers - This is literally "you who continuously believed", believed as a lifestyle.