The "spirits in prison"? Who are they, and why did Jesus visit them?

The Bible Unbound - Book of Revelation

Jesus went through three "doorways" in His experience of death and resurrection. Besides the cross and His rising, He seems to have done some visiting around. Here's how Peter states it in his first epistle: "For Christ also suffered once for sins, the righteous for the unrighteous, that he might bring us to God, being put to death in the flesh but made alive in the spirit, in which he went and proclaimed to the spirits in prison, because they formerly did not obey, when God’s patience waited in the days of Noah, while the ark was being prepared, in which a few, that is, eight persons, were brought safely through water..."
In this episode, we examine that mysterious chapter in our Lord's journey of redemption of mankind. Why did He descend into the "prison" and who were these "spirits"?
These questions have raised speculation through the ages, but scripture is actually quite clear on the subject. This is the topic under consideration in this podcast episode.
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