1 Corinthians 16:21

Paul customarily dictated his letters, and a secretary wrote them down (cf. Romans 16:22). However, he usually added a word of greeting at the end in his own hand that authenticated his epistles as coming from him (cf. Galatians 6:11; Colossians 4:18; 2 Thessalonians 3:17). All of what follows is probably what he added.