"By whom also He went and preached to the spirits in prison"
In 1 Peter 3:19-21 Peter focuses on two great judgments:
1) the judgment of Noah’s day and
2) the judgment of fallen angels.
Peter presents the ark of Noah’s day as the type of Christ’s suffering on the cross. In verse 21 he gives the antitype (the reality behind the type) as salvation by Christ’s baptism at Calvary.
By whom also
The remainder of this chapter is very difficult to interpret. The best interpretation is that Christ descended into Hades after his resurrection to proclaim to fallen angels that their fall was unnecessary (2 Peter 2:4-5). This interpretation would equate the fallen angels with the “sons of God” in Genesis 6:1-2.
”By whom” refers to the Holy Spirit. The Holy Spirit transported Jesus to Tartarus and enabled him to preach to fallen angels.
He went and preached to the spirits in prison
“He” refers to the Lord Jesus.
”Went” — to be transported. The Holy Spirit transported Jesus to Tartarus, the residence of fallen angels. Tartarus is not hell but an underworld for demons (2 Peter 2:4; Jude 6).
We better translate the word “preached” as, made an official announcement. This is different from the usual word to preach. It means to make an official announcement by a public crier. The issue is not the gospel here but a victorious proclamation to fallen angels that they did not have to fall because Jesus did not fall. Verse 20 clearly indicates to whom he made the announcement.
Jesus here asserts his triumph over the sin issue. Jesus came to undo the original fall — the fall of angels. Angels were tested and failed. Jesus was tested and succeeded.
“Having disarmed principalities and powers, He made a public spectacle of them, triumphing over them in it” (Colossians 2:15).
“To the spirits in prison” — fallen angels of Genesis 7 (2 Peter 2:4). This was an angelic infiltration into the human race. These angles could not repent but they were brought to subjection (verse 22).
God will one day vindicate Himself.
God demonstrates His vindication of Christ in the resurrection. In His ascension, God seated Him above all angelic powers. As we embrace new life in Christ, we too overcome what brought the angels down.