Consider Colossians 4:7-9:
Tychicus will tell you all about my activities. He is a beloved brother and faithful minister and fellow servant in the Lord. I have sent him to you for this very purpose, that you may know how we are and that he may encourage your hearts, and with him Onesimus, our faithful and beloved brother, who is one of you. They will tell you of everything that has taken place here.Why does Paul say of Onesimus that he "is one of you"? Presumably, this indicates that Onesimus himself was a Colossian. Do we have any independent evidence for Onesimus being a Colossian?
Turn with me to the book of Philemon. In this epistle, we learn that Onesimus had been a slave of Philemon, had run away and encountered the apostle Paul on his travels, who brought him to a saving knowledge of the gospel. Paul then wrote a letter to Onesimus's master, Philemon. Take a look at the epistle's address, given in verses 1-2:
To Philemon our beloved fellow worker and Apphia our sister and Archippus our fellow soldier, and the church in your house.The text does not tell us where Philemon is from. However, there is mention made of a certain Archippus, who must be from the same city as Philemon (and by extension Onesimus). The epistle to Philemon nowhere tells us where Archippus is from either. However, when we turn back to Colossians 4, we find that there is an instruction given in verse 17:
And say to Archippus, “See that you fulfill the ministry that you have received in the Lord.”Since Paul is writing to the church in Colossae, and since Paul gives his audience the instruction to pass on a message to Archippus, this indicates to us that Archippus was living in Colossae. Since the epistle to Philemon makes the connection of Onesimus to Philemon, and Philemon to Archippus, this indicates by extension that Onesimus is likewise from Colossae, thus illuminating Paul's words in Colossians 4:9: "Onesimus...who is one of you." This also indicates that Paul must have written the epistle to the Colossians and the epistle to Philemon at around the same time, while Onesimus was with him in Rome before returning to his master Philemon.
This undesigned coincidence supports the Pauline authorship of the epistle to the Colossians. It also corroborates the historical veracity of the story of which we read in the book of Philemon.