1 Peter 3:19

In it ¹  he went and preached to the spirits in prison, ² 

through whom also he went and preached to the spirits in prison

in which also He went and made proclamation to the spirits now in prison,

So he went and preached to the spirits in prison––

He went and proclaimed God's salvation to earlier generations who ended up in the prison of judgment

By whom he went to the spirits in prison, preaching to those

in which also he went and made a proclamation to the spirits in prison,

by whom also He went and preached to the spirits in prison,

In it ¹  he went and preached to the spirits in prison, ² 

¹ tn Grk “in which.” ExSyn 343 notes: “The antecedent of the RP [relative pronoun] is by no means certain. Some take it to refer to πνεύματι immediately preceding, the meaning of which might be either the Holy Spirit or the spiritual state. Others see the phrase as causal (‘for which reason,’ ‘because of this’), referring back to the entire clause, while still other scholars read the phrase as temporal (if so, it could be with or without an antecedent: ‘on which occasion’ or ‘meanwhile’). None of these options is excluded by syntax. It may be significant, however, that every other time ἐν ᾧ is used in 1 Peter it bears an adverbial/conjunctive force (cf. 1:6; 2:12; 3:16 [here, temporal]; 4:4).” Also, because of the length and complexity of the Greek sentence, a new sentence was started here in the translation.

² sn And preached to the spirits in prison. The meaning of this preaching and the spirits to whom he preached are much debated. It is commonly understood to be: (1) Christ’s announcement of his victory over evil to the fallen angels who await judgment for their role in leading the Noahic generation into sin; this proclamation occurred sometime between Christ’s death and ascension; or (2) Christ’s preaching of repentance through Noah to the unrighteous humans, now dead and confined in hell, who lived in the days of Noah. The latter is preferred because of the temporal indications in v. 20a and the wider argument of the book. These verses encourage Christians to stand for righteousness and try to influence their contemporaries for the gospel in spite of the suffering that may come to them. All who identify with them and their Savior will be saved from the coming judgment, just as in Noah’s day.