Question: Could you explain what "suffer in the flesh" (1 Peter:4:1) means and whether it is part of God's chastisement?
Response: In context, Peter is addressing the finished work of Christ and its application to believers. Christ died on the Cross. That He "suffered in the flesh" is a synonym for that death. In like manner, Christians are to "reckon ye also yourselves to be dead indeed unto sin, but alive unto God through Jesus Christ our Lord" (Rom:6:11).
To a dead man, sin no longer has any appeal. We may parade any temptation past a dead man. None will entice him. Peter goes on in chapter 4 to explain, "For the time past of our life may suffice us to have worked the will of the Gentiles, when we walked in lasciviousness, lusts, excess of wine, revelings, parties, and abominable idolatries: Wherein they think it strange that ye run not with them to the same excess of riot, speaking evil of you" (1 Pt 4:3-4).
Finally, it is certain that this passage does not support the false idea (as portrayed in The Passion of the Christ) that physical sufferings bought our salvation. It was through the death, burial, and resurrection of Jesus that Satan, the serpent, would be destroyed (see TBC 10/09).