This is the weekly Q & A blog post by our Research Professor in Philosophy, Dr. William Lane Craig.
In last weeks Defenders class (2019.08.11) you noted that you have become persuaded that mankind was not created in a state that they were, by nature, immortal. This would imply that physical death is not the punishment for sin. If physical death is not the punishment for sin, how is it possible to consider Jesus crucifixion to be punishment? I can understand how we would be able to view the crucifixion as Jesus sacrificial offering but, given that physical death is not a punishment of sin, it would be hard to describe the cross as punishment and, given a penal substitutionary theory of the atonement, we would need to point to what punishment Jesus did suffer as our representative, our proxy.
Dr. William Lane Craig's Response
In my study of I Corinthians 15.22-23, 45-49 and Romans 5.12-21, it became clear to me that Paul is addressing two different problems: on the one hand physical death and on the other spiritual death. In I Corinthians 15 Paul does not ascribe Adam’s physical death to his Fall, but, citing Genesis 2.7, to his creation. We are created with a natural, mortal body whose mortality will be reversed only with the resurrection. In Romans 5 Paul is dealing with spiritual death, the condemnation and alienation from God that is reversed by Christ’s atoning death on the cross and our justification through faith.
Physical death is not the result of Adam’s Fall, except in the indirect sense that his Fall led to his expulsion from the Garden and so forfeiting any chance of immortality by eating of the Tree of Life. So physical death is not a punishment for sin, except when administered by the state prematurely for capital crimes. We are naturally mortal. Our natural mortality makes it plain why Jesus, though sinless, had a mortal body that could be killed.
The punishment for sin which Jesus bore on our behalf was not merely physical death. So thinking would leave you open to Socinian objections that his physical suffering and death could not come close to atoning for all the sins of mankind and the satisfaction of divine justice for every man. Rather Christ experienced on the cross the spiritual death which is the punishment for sin, the separation and alienation from God that is our just desert. As the Reformed theologian Francis Turretin so eloquently explained, on the cross Christ was forsaken by God the Father by His withdrawing from him the beatific vision and by suspending the joy and comfort and sense and fruition of full felicity. That is the true punishment for sin.
 Francis Turretin, Institutes of Elenctic Theology, 3 vols., trans. George Musgrave Giger, ed. James T. Dennison (Phillipsburg, N. J.: Presbyterian and Reformed, 1992), vol. 2, Topic 14, Question 11
This Q&A and other resources are available on Dr. William Lane Craig's website.