A Biblical word study in ESV. May God grant me the endurance to see this study carried out.
1 Peter 3:18-20 — “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.”
MacArthur commentary for 1 Peter 3:19: “Between Christ’s death and resurrection, his living spirit went to the demon spirits bound in the abyss and proclaimed that, in spite of his death, he had triumphed over them…’spirits in prison’ [refers] to fallen angels (demons), who were permanently bound because of heinous wickedness. The demons who are not so bound resist such a sentence (cf. Luke 8:31). In the end, they will all be sent to the eternal lake of fire (Matt. 25:41; Rev. 20:10).”
MacArthur commentary for 1 Peter 3:20: “Peter further explains that the abyss is inhabited by bound demons who have been there since the time of Noah, and who were sent there because they severely overstepped the bounds of God’s tolerance with their wickedness. The demons of Noah’s day were running riot through the earth, filling the world with their wicked, vile, anti-God activity, including sexual sin, so that even 120 years of Noah’s preaching, while the ark was being built, could not convince any of the human race beyond the eight people in Noah’s family to believe in God…thus God bound these demons permanently in the abyss until their final sentencing.”