With this clause Peter draws out the goal of Jesus’ undeserved suffering: Jesus had a broader goal in mind than the eye saw as he was stripped of his clothes, whipped, insulted, crucified. Recall that Peter had said in 1 Peter 3:14 that even if his readers should wrongly suffer, you will be blessed.
In Jesus’ case the “blessing” was not (in this verse) for Jesus himself but for us
; through his suffering Jesus brought the unrighteous to God. There is a parallel with 1 Peter 3:14 that is critical to Peter’s argument.
18 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,