Building on our discussion of the divinity of Jesus Christ, we turn to what the bible says Christ did on the cross. What is penal substitutionary atonement? The bible teaches that Christ died as a substitute for sinners, and suffered the wrath of God they justly deserved. We point out the biblical foundation for this belief and its importance for understanding the gospel. We also interact with the arguments of Greg Boyd, who criticizes PSA, and deal with a number of misrepresentations of the doctrine.