I. Howard Marshall, in his book Aspects of the Atonement, helpfully sets out some of the questions that need to be asked about the doctrine of penal substitutionary atonement:-

1. What is the place of penal substitution in the teaching of Scripture? There are four distinguishable views:

• The principle of penal substitution does not figure in the New Testament at all.
• It is there, but it is only one of the pictures/metaphors/analogies used in the New Testament to express the significance of the death of Jesus Christ. Some might argue that in this case it is of lesser importance or even dispensable.
• It occurs to such an extent that it is not only indispensable but also the most important.
• It is the underlying principle present in all the others and the factor that makes them cohere.

2. Is the doctrine, in fact, based on a correct understanding of the theological statements about the death of Jesus in Scripture? There is considerable debate over the nature of sacrifice, for example, whether sacrifice in the Old Testament functioned by virtue of penal substitution of the animal sacrificed for the sinner.

3. Even though it may be taught in Scripture, is it a doctrine that we can maintain today, or is it surrounded by such objections as to make it unacceptable? Here such questions arise as:

• What is the nature of punishment? Is it retributive, or what? Bound up with this is the understanding of what is meant by guilt.
• Is substitutionary suffering an appropriate, ethical way of saving sinners from the consequences of their sin?

4. Are there other understandings of the New Testament teaching about the death of Jesus that may be regarded as more basic than penal substitution or that may be held alongside it as parts of a total understanding of that death?

5. How are other aspects of the life and work of Jesus related to our salvation, and how do they fit in with this doctrine? In particular, how does the resurrection fit into the picture as a saving event?

6. How do we present and explain the death of Christ in our preaching and evangelism today?

(Emphasis added)