While Paul was sitting in prison, contemplating his upcoming trial and potential work in the west, he began formulating some parting comments to make to the churches of Asia Minor. As he dialogued with his amanuensis over its contents, a rough draft of Ephesians was probably put together in outline form. The amanuensis then began to fill in the details.

Then, startling news from the east came: there was a new heresy in Colossae which was infecting the church there. At about the same time, Onesimus appeared before Paul with his confession of abandoning and robbing his owner, Philemon.

At this juncture, Paul decided several things: (1) write to the Colossians with appropriate warnings, though taking the material mostly from a letter which already addressed some of the very same issues in a larger perspective; (2) write to Philemon, urging him to take Onesimus back, as a freeman—and even to prepare a room for the apostle himself; (3) finish the letter to all the churches in Asia Minor and have it sent with the other two letters.

If this reconstruction is correct, it fits several pieces of the puzzle: (1) the reason Ephesians looks so much like Colossians is because one letter was intentionally used as the basis for the other, with some necessary modifications made to fit the occasion. (2) The reason Ephesians does not look like the rest of Paul’s letters (except Colossians) in style or vocabulary is because (in part) it was done as a contemplative piece, originally intending to be something of a swan song, summing up Paul’s theology for the churches in Asia. (3) Since Colossians is an occasional letter, written with some urgency, the only way for a contemplative letter like Ephesians to have been sent at the same time is for Ephesians to have been written (at least in draft form) prior to Colossians. (4) When Paul learned of the new influx of heresy he changed his plans of going westward and decided to visit Asia one more time. This would not alter the fact that Ephesians was intended to be a reflective summary of his theology, but the initial occasion for the writing of Ephesians was a short-lived one which evaporated with news from Colossae.

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Colossians 1:1