1 Corinthians 16:21

Own hand. Apparently Paul customarily employed a secretary to write his letters to the churches. He gave authenticity to the epistle by signing his name and expressing his greetings to the brethren (cf. Col. 4:18; 2 Thess. 3:17). This signature formed a proof that the contents of the letter were truly his, as well as an indication of his loving regard for the church. He had been troubled by those who had forged letters purporting to be his (see on 2 Thess. 2:2), and his personal signature was intended to foil the designs of such men.