Paul, Silas, & Timothy reminds the Thessalonians in the Truth of their testimony to Thessalonians by reminding the Thessalonians of their earlier actions.

1 Thessalonians 1:1, 1 Thessalonians 2:5, 1 Thessalonians 2:7-9, 1 Thessalonians 2:7, 1 Thessalonians 2:9 and 1 Thessalonians 2:11-12