Paul, Silvanus, and Timothy, to the assembly of the Thessalonians in God the Father and the Lord Jesus Christ: Grace to you and peace from God our Father and the Lord Jesus Christ.
Paul: In the letter to the Thessalonians, Paul does not, as in some of his letters, immediately identify himself as an apostle. "He does not add ’an apostle,’ &c., because in their case, as in that of the Philippians (Philippians 1:1), his apostolic authority needs not any substantiation" (Jamieson, Faucet, and Brown 384). Noting that Paul’s official title "Apostle" is omitted in the introduction to both Thessalonian letters, Vincent adds: "The title appears in all the other Epistles except Philippians and Philemon. The reason for its omission in every case appears to have been the intimate and affectionate character of his relations with the parties addressed, which rendered an appeal to his apostolic authority unnecessary" (Vol. IV 9). The appeal to apostolic authority in Paul’s later letters becomes necessary as his enemies increasingly call it in question. While Paul’s name is joined with those of Silvanus and Timotheus in the salutation, it is clear that Paul is the principal author of this letter.