Jesus' "preaching" to the fallen angels followed his resurrection. The message was about his victory in dying faithfully, providing the means of salvation to humans, and gaining his right to kingship.
1 Tim. 3:16 Indeed, the sacred secret of this godly devotion is admittedly great: ‘He was made manifest in flesh, was declared righteous in spirit, appeared to angels, was preached about among nations, was believed upon in the world, was received up in glory.’
That claim and its "proof-text" are rather insubstantial. IMHO
Where was Jesus for the three days BEFORE his resurrection?
Matthew 12:40
For as Jonah was three days and three nights in the belly of a huge fish,
so the Son of Man will be
three days and three nights in the heart of the earth.
Note: Christ was laid in an above ground tomb.
Where is the heart of the earth?
Answer: the realm of the dead
1 Peter 3:18-20
For Christ also suffered once for sins, the righteous for the unrighteous,
to bring you to God. He was put to death in the body but made alive in the Spirit.
19 After being made alive, he went and made proclamation to the imprisoned spirits—
20 to those who were disobedient long ago when God waited patiently in the days of Noah
while the ark was being built. In it only a few people, eight in all, were saved through water,
Ephesians 4:8-10
This is why it says: “When he ascended on high, he took many captives and gave gifts to his people.”
9 (What does “he ascended” mean except that he also descended to the lower, earthly regions?
10 He who descended is the very one who ascended higher than all the heavens, in order to fill the whole universe.)
1 Peter 4:6 NRSV
For this is the reason the gospel was proclaimed even to the dead, so that,
though they had been judged in the flesh as everyone is judged, they might live in the spirit as God does.
Romans 14:9
For this very reason, Christ died and returned to life so that he might be the Lord of both the dead and the living.
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