Any notion of penal substitution in which three independent actors play a role – the guilty party, the punitive judge and the innocent victim – is to be repudiated with the utmost vehemence.  It would not only be unjust in itself but would also reflect a defective Christology. For Christ is not an independent third person, but the eternal Son of the Father, who is one with the Father in his essential being. What we see, then, in the drama of the cross is not three actors but two, ourselves on the one hand and God on the other. Not God as he is in himself (the Father), but God nevertheless, God-made-man-in-Christ (the Son).

—The Cross of Christ, 158.