Colossians 4:16

the epistle from Laodicea--namely, the Epistle which I wrote to the Laodiceans, and which you will get from them on applying to them. Not the Epistle to the Ephesians. See Introduction to Ephesians and Introduction to Colossians. The Epistles from the apostles were publicly read in the church assemblies. IGNATIUS [Epistle to the Ephesians, 12], POLYCARP [Epistle to the Philippians, 3.11,12], CLEMENT [Epistle to the Corinthians, 1. 47], Th1 5:27; Rev 1:3, "Blessed is he that readeth, and they that hear." Thus, they and the Gospels were put on a level with the Old Testament, which was similarly read (Deu 31:11). The Holy Spirit inspired Paul to write, besides those extant, other Epistles which He saw necessary for that day, and for particular churches; and which were not so for the Church of all ages and places. It is possible that as the Epistle to the Colossians was to be read for the edification of other churches besides that of Colosse; so the Epistle to the Ephesians was to be read in various churches besides Ephesus, and that Laodicea was the last of such churches before Colosse, whence he might designate the Epistle to the Ephesians here as "the Epistle from Laodicea." But it is equally possible that the Epistle meant was one to the Laodiceans themselves.

I. He continues his account of the duty of masters, from the close of the former chapter (Col 4:1). II. He exhorts to the duty of prayer (Col 4:2-4), and to a prudent and decent conduct towards those with whom we converse (Col 4:5, Col 4:6). III. He closes the epistle with the mention of several of his friends, of whom he gives an honourable testimony (Col 4:7-18).

4:16 you should read the letter I wrote to them: Various attempts have been made over the years to identify the letter to the Laodiceans with a New Testament letter or fragment, but it is most likely that Paul’s letter to the Laodicean church has been lost.