To send (and hence receive) greetings
is more than saying (and acknowledging) hello. Christian greetings imply the wish (or prayer) for God’s peace and blessing upon the recipient (see Matthew 10:12–13). With the sending of greetings, then, the church in Babylon was expressing its wish (or prayer) that Peter’s suffering readers would experience the nearness and peace of God in the midst of their trials. That in turn is to say that Peter’s readers should know that they were not alone in their struggles. Irrespective of what their brothers and sisters in Babylon were experiencing (in the nature of things as Peter drew out in his letter, it would be similar to his readers), they should know that others were praying for them because of their love for their fellow saints. This is encouraging.
13 She who is at Babylon, who is likewise chosen, sends you greetings, and so does Mark, my son.