Albert Barnes on Ephesians 6:22

Whom I have sent unto you. The churches where Paul had preached, would feel a great interest in his welfare. He was a prisoner at Rome, and it was doubtful what the result would be. In this situation, he felt it proper to despatch a special messenger to give information about his condition; to state what was doing in Rome; to ask the prayers of the churches; and to administer consolation to them in their various trials. The same sentiment, in regard to the embassy of Tychicus, is expressed in the epistle to the Colossians, Col 4:7,8. No small part of the consolation a which he would impart to them would be found in these invaluable letters which he bore to them from the apostle.

(b) "have sent" Col 4:7,8