Satisfaction models argue that as a result of their sinfulness, human beings have a debt or obligation to God that they cannot possibly repay. By becoming incarnate, living a sinless life, and voluntarily dying for the sake of humanity, Christ successfully discharges the debts and obligations that human beings owe to God. Anselm’s “Why God Became Human” (Cur deus homo) is the locus classicus for the satisfaction theory, which has more recently been defended by Swinburne (1988). Closely related to satisfaction models, penal substitution models claim that human beings deserve punishment from God as a result of their sinfulness. Christ saves by freely agreeing to be punished in their place. Mark Murphy (2009) proposes a similar model of “vicarious punishment”, on which Christ’s suffering actually counts as the required punishment for guilty human beings, since knowing that a loved one suffers in one’s place is itself a form of punishment.