That ye also - As well as other Churches to whom I have communicated the dealings both of God and man to me.
May know my affairs - May be acquainted with my situation and circumstances.
And how I do - How I employ my time, and what fruit there is of my apostolical labors.
Tychicus, a beloved brother - We learn, from Act 20:4, that Tychicus was of Asia, and that he was a useful companion of St. Paul. See the note on Act 20:4.
This same person, and with the same character and commendation, is mentioned in the Epistle to the Colossians, Col 4:7. He is mentioned also in Tit 3:12, and in 2Ti 4:12; from all these places it is evident that he was a person in whom the apostle had the highest confidence, and that he was a very eminent minister of Christ.