Colossians 4:9
With Onesimus, a faithful and beloved brother, who is one of you. They shall make known unto you all things which are done here.
Cross-reference
Philemon 1:10–19
Historical context
Philemon 1:10-19 provides the full story of Onesimus's conversion and return — the runaway slave now sent back as a dear brother.
Ephesians 6:21
Historical context
Ephesians 6:21 describes Tychicus, the same faithful servant sent with Onesimus — giving complementary details about his role.