John Calvin on 1 Peter 3:18

18 For Christ also It is another comfort, that if in our afflictions we are conscious of having done well, we suffer according to the example of Christ; and it hence follows that we are blessed. At the same time he proves, from the design of Christ’s death, that it is by no means consistent with our profession that we should suffer for our evil deeds. For he teaches us that Christ suffered in order to bring us to God. What does this mean, except that we have been thus consecrated to God by Christ’s death, that we may live and die to him?

There are, then, two parts in this sentence; the first is, that persecutions ought to be borne with resignation, because the Son of God shews the way to us; and the other is, that since we have been consecrated to God’s service by the death of Christ, it behoves us to suffer, not for our faults, but for righteousness’ sake.

Here, however, a question may be raised, Does not God chastise the faithful, whenever he suffers them to be afflicted? To this I answer, that it indeed often happens, that God punishes them according to what they deserve; and this is not denied by Peter; but he reminds us what a comfort it is to have our cause connected with God. And how God does not punish sins in them who endure persecution for the sake of righteousness, and in what sense they are said to be innocent, we shall see in the next chapter.

Being put to death in the flesh Now this is a great thing, that we are made conformable to the Son of God, when we suffer without cause; but there is added another consolation, that the death of Christ had a blessed issue; for though he suffered through the weakness of the flesh, he yet rose again through the power of the Spirit. Then the cross of Christ was not prejudicial, nor his death, since life obtained the victory. This was said (as Paul also reminds us in 2 Corinthians 4:10) that we may know that we are to bear in our body the dying of Christ, in order that his life may be manifested in us. Flesh here means the outward man; and Spirit means the divine power, by which Christ emerged from death a conqueror.

1 Peter 3:19-22

19. By which also he went and preached unto the spirits in prison;

19. In quo et iis qui in specula (vel, in excubiis, vel, carcere) erant spiritibus, profectus prædicavit;

20. Which sometime were disobedient, when once the long-suffering of God waited in the days of Noah, while the ark was a preparing, wherein few, that is, eight souls were saved by water.

20. Quum inereduli fuissent olim, quum semel expectabatur Dei patientia in diebus Noe; dum apparabatur arca, in qua paucae, hoc est, octo animae servatae sunt per aquam.

21. The like figure whereunto even baptism doth also now save us (not the putting away of the filth of the flesh, but the answer of a good conscience toward God,) by the resurrection of Jesus Christ:

21. Cujus figura respondens baptismus, nos quoque salvos reddit, non abjectio sordium carnis, sed bonae conscientiae examen apud Deum, per resurrectionem Jesu Christi:

22. Who is gone into heaven, and is on the right hand of God; angels and authorities and powers being made subject unto him.

22. Qui est in dextera Dei profectus in coelum, subjectis sibi angelis, et potestatibus et virtutibus.