gengwall

I will add – in Collosians 3:18 hupotasso is in middle voice, just as it is in Ephesians 5:22, in the Textus Receptus and the Majority text. In NA26, hupotasso is passive in Col 3:18 and Ephesians 21, and absent in Ephesians 22 where it is derived from vs. 21. What resource are you looking at that has it as an imperative in Col 3:18. I am looking at scripture4all.org (TR) and studylight.org (NA26) for my parsing.

Susanna has an appendix in her book which shows how Ephesians and Collosians are really the same letter to different audiences. My point is that Paul does not alter the voice between the two – it is no more imperative in Collosians than it is in Ephesians.