Peter is drawing attention to the fact that Jesus’ death was not an accident. It was engineered and carried out by human beings and yet at the same time it was also the climax of God’s plan of salvation (see Isaiah 53:12; Luke 22:22; 1 Peter 1:20–21). Here we come face to face with the biblical teaching that God is sovereign and completely in control of all that happens and yet man is nonetheless responsible for what he does. What the Jews did freely and culpably is what the holy and good God had eternally foreordained to come to pass.1
23 this Jesus, delivered up according to the definite plan and foreknowledge of God, you crucified and killed by the hands of lawless men.