In my book I argue that there is no coherent understanding of the atonement. Here are some questions for those who accept the penal substitutionary view ...In the first part he reminds me of Michael Martin, an atheist philosopher whom I answered at length on the atonement1. With the current piece, there are a few problems right off the bat: First, a great many Christians (myself included) believe that the penal substitutionary view shortchanges the Biblical view of atonement. If he's holding out for a coherent view of the penal substitutionary theory of atonement in particular, I will leave that to people who subscribe to it, hoping that the skeptic is not merely using it as a gift straw man.2 Then the skeptic takes a Webster's definition of forgiveness instead one native to the sacrificial system which the Bible understands, with the intrinsic relationship between sin and death, and the sinner's participation in the sacrifice by putting to death the sin inside himself. The questions also draw no distinction between forgiveness and overlooking sin, or between justice and revenge. There seems to be no appreciation that giving evil a free pass is a bad thing, and that God's forgiveness cannot be a license for evil.
But I'd like to focus within the questions presented on what seems to be the biggest misunderstanding of Christian theories of atonement: the skeptic does not seem to grasp that Christ's being one with God has any effect on whether God is "retaliating" or taking "sweet revenge" on "someone else". God is, in fact, doing very much the opposite: he is the one suffering, he is the one dying, he is the one taking the punishment of the law and the viciousness of human hatred. The charge that he is being unfair to someone else overlooks the entire doctrine of the incarnation, the person and nature of Christ. Here is an example: if a man ran a red light and totalled my car, and he paid his own traffic ticket, that is simple justice by our current laws. If he could not pay his own ticket and some kind stranger paid on his behalf, that would be benevolence. If I paid the traffic ticket for the man who totalled my car, that is a mind-boggling level of mercy; it closer to what God does for us.
But that is still addressed to a transaction theory of atonement. A fuller understanding of atonement requires recognition that our being transformed from enemies of God to children of God requires something far more profound than a transaction.3
1 - Though Martin's favorite "orthodox" view of atonement was Origen's ransom theory, which Martin used as a gift straw man to discuss atonement.
2 - Those who hold the penal substitutionary view will know best whether he represents their views correctly. But if he does, that still does not mean he represents Christian theology correctly.
3 - For full length treatments of the atonement, I'd recommend Athanasius' On the Incarnation of the Word of God and, more recently, Gerhard O. Forde's Where God Meets Man. For those who would rather have a blog-length linked piece I've done a short round-up of some of my own with the understanding that the reader beware; I'm an amateur. The list excludes some already linked in the main response above. They are at least freebies:
Sin, Ignorance, and Judgment
Sin, Repentance, and Forgiveness
Forgiveness, Sacrifice, and Christ
Forgiveness and Sacrifices Offered for the Unaware
Condemnation and the Ancient Gentiles
The Unfairness of Heaven? (on the justification of Judgment Day)