enlightening To quote or at least paraphrase Richard, "Martin Luther couldn't figure this out, but I have it nailed." He said it jokingly, but it illustrates the difficulty of understanding this passage.
Your exposition of this passage has given me a lot to think about Richard. My interpretation of verse 18-22 was different. However, the way you illustrated who these spirits were, and used Scriptures (II Peter 2:1-6, Jude 6-7 and Genesis 6) appears to show exactly what you shared.
I was not accepting that Christ preached in Hades, because He did not suffer there for our sins. He said on the cross that "it is finished." However, I see now that such a position does not mean that Jesus could not have gone there and proclaimed something to the Spirits.
One question. I am not a Greek scholar. But doesn't the word for "made alive" in verse 18 mean to make alive/reanimate rather than keep alive?
It is always edifying to listen to such excellent expository preaching.