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.
The absence of any reference to Paul’s apostleship in any of his inspired writings to the Macedonian churches, namely, those in Thessalonica and Philippi, is noteworthy. He mentioned his apostleship in all his other epistles and sometimes had to defend it vigorously (e.g., in 2 Corinthians). Evidently the Macedonian churches never questioned Paul’s apostleship as did the churches elsewhere (e.g., in Galatia and Corinth).