Colossians 4:16

Verse 16. And when this epistle is read among you, cause that it be read also in the church of the Laodiceans. Laodicea was near to Colosse, and the church there was evidently exposed to the same dangers from philosophy and false teachers as that at Colosse. The counsels in this epistle, therefore, would be equally applicable to both. In 1 Th 5:27, the apostle also charges those to whom that epistle was addressed to see that it be "read unto all the holy brethren." It is evident that the apostles designed that the letters which they addressed to the churches should be read also by others, and should become the permanent source of instruction to the friends of Christ.