A lot of criticisms leveled against penal substitution (PSA) are based upon the fact that PSA is far to commercial in nature. It makes it seem as though God is subject to some abstract economic theory over which he is not sovereign. It is also said that it makes atonement a cold unloving action in which we are only forgiven because we met some abstract rule rather than saying we are forgiven simply because God loves us. Now I must say that these are some pretty weak objections, nevertheless, it must be pointed out that all the “commercial” stuff behind atonement is just a God given-inspired metaphor for the mystery of atonement. We must not push the metaphor too far and we must not make it the sole controlling metaphor. Note what Geerhardus Vos has to say about this in Reformed Dogmatics Volume One: Theology Proper…
110. Must the exercise of punishment be understood as a purely commercial transaction?
No, it may not. There is a manifold difference between paying a financial debt and punishment for guilt, as the doctrine of atonement will show. Punishment is the restoration of relationship, of the status of sinners in relation to God, not taking back something that was first taken from God. (p. 33)
So there you have it, atonement is not merely a commercial transaction. It is a restoration of relationship. However, what is interesting is that Vos seems to completely disavow a satisfaction theory in this brief statement. Contra Anslem, and others who see atonement as Christ giving God what is due on our behalf, Vos says that atonement (PSA) does not such thing. I can’t wait till further translations of Reformed Dogmatics come out so I can further explore this.