At first read we get the impression that Silvanus served as Peter’s secretary (by Silvanus…I have written), and Peter is simply honest enough to mention that. For a couple of reasons, however, we have to conclude that more is happening here. The particular preposition Peter uses (by Silvanus) is used in parallel situations in Scripture to refer not to a secretarial role but to being the letter’s courier (see the Greek of Acts 15:23: with). Further, Peter’s assessment of Silvanus as a faithful brother serves no purpose if he is nothing more than Peter’s secretary, whose work in recording Peter’s dictation accurately Peter could personally double-check before sending the letter. That Peter regards Silvanus as a faithful brother makes abundant sense if Silvanus is the courier who has to deliver Peter’s letter, and so answer potential questions on the letter.