I realize that the title is a wholly anachronistic view of these two books. I admit and I own my guilt, if not shame, here. However, I cannot think of a better analogy by which to view these two books.
In reading these books for Sunday School class, in which we surface grazed both books, I read Ephesians first, giving preference to both the canonical order and my favorite of the two. However, in discussing some of this on Facebook that Saturday evening, Jeremiah Bailey said he felt like Ephesians was an expansion of Colossians. While I am not so sure as he is about that, and since he never offered up a second opinion, I am hesitant to cast my lost with him. Yet, there are some expansive elements in Ephesians developed from Colossians. I can admit that.
I would classify Colossians-Ephesians as a Deutero-Pauline book set for a variety of reasons. First, Colossians carries something of 2 Corinthians in it and seems to really develop certain themes from 2 Corinthians 5. Ephesians, however, develops Romans 8 extensively while pulling the developed Christology from Colossians. Thus, I think Brian LePort is most correct via our conversation on Facebook.
The reason I would anachronistically call Colossians the Declaration of Independence is because there is still a tinge of impetus in the letter. The author is writing against a few things. I find a possible impetus in 2.8, or rather two impetuses. The first are the Greeks (maybe proto-Gnostics of some sort) and the Jews who do not believe in Jesus as Messiah. I say this because of the remark of philosophy and the elementary principles of the world, with the latter phrase referencing the Law of Moses and the former the empty (a pun?) philosophy of proto-Gnostics.
Ephesians carries almost no trace of opposition, but instead establishes the cause of the Church, the mission of the Church, and the operations of the Church. One thing I will point out here, is that our chapter 3 of Ephesians is strikingly Pauline. It includes a greeting and a benediction, amen. Perhaps Ephesians is built around this letter by Paul as a way to give a wider authority to the whole of the letter. This is, at best, circumstantial.
Anyway, these are just some thoughts on these two books.
Next week, we are reading through the pastorals, the pseudo-Pauline books.