Adam Clarke on Ephesians 6:22

Whom I have sent - for the same purpose - Namely, that the Ephesians might know his affairs, and those of the Church at Rome: messengers of this kind frequently passed between the Churches in those ancient times.

Comfort your hearts - By showing you how powerfully he was upheld in all his tribulations, and how God turned his bonds to the furtherance of the Gospel. This must have been great consolation to all the followers of God; and particularly to those in Ephesus or Laodicea, or to whomsoever the epistle was directed. The question, To whom was it sent? is divided between the Ephesians and the Laodiceans. Dr. Lardner has argued strongly in favor of the former; Dr. Paley not less so in favor of the latter.