“By whom also He [Christ] went and preached to the spirits in prison, who formerly were disobedient, when once the Divine longsuffering waited in the days of Noah, while the ark was being prepared, in which a few, that is, eight souls, were saved through water.” – 1 Peter 3:19-20
“These are of the number of the stars [of heaven], which have transgressed the commandment of the Lord, and are bound here till ten thousand years, the time entailed by their sins, are consummated.” – 1 Enoch 21:6
According to Genesis 6:1-4, some “sons of God” (angels) fell in love with and married beautiful “daughters of men” (human women), and even had children with them, who were “the heroes of old, men of renown.” The Bible cites these relationships as a major contributing factor to the Noahide Flood. It doesn’t mention a punishment upon the angels involved, but oral tradition does. This oral tradition was later written down in several Jewish writings; one of these writings is 1 Enoch. In 1 Enoch, the Prophet Enoch goes to these angels who were bound in their temporary punishment to proclaim to them the coming Final Judgment of God. The New Testament authors saw in this a parallel with Christ’s harrowing of hell and, especially for St. Peter, viewed Enoch as a prototype of Christ in this respect.