Athanasius and Penal Substitution
Athanasius was a particularly influential and controversial theologian in the fourth century AD. One of his works is a medium-length detailed analysis of his views on the atonement, called On the Incarnation of the Word.
The main model of atonement he spells out there is called Recapitulation, or the Incarnational Model. This model conceives of the problem facing creation as being that it is decaying into non-existence due to separation from God. The solution is therefore for God to unite himself metaphysically to the created order, and this was achieved through his becoming man. In the person of Jesus Christ, God and man were perfectly united and therefore by virtue of Jesus' human life creation was saved from non-existence. Jesus' act in this manner is universal in its effects - all creation has been saved from non-existence. Now we have immortality and eternal existence provided for us by virtue of this saving action of Jesus.
This does not however mean that immortal existence is necessarily going to be happy for us - there is still the final judgment of God to heaven or hell. Clearly prior to Jesus' saving us from non-existence there could be neither heaven nor hell nor final judgment, as our souls would have simply ceased to exist. Athanasius takes the view that final judgment is judged according to virtue, and that Christ was a teacher of how to live a virtuous life and by following his teachings we can achieve a positive judgment. Thus, for example, in the conclusion to his On the Incarnation he writes:
[Christ] will Himself be Judge, judging each and all according to their deeds done in the body, whether good or ill. Then for the good is laid up the heavenly kingdom, but for those that practice evil outer darkness and the eternal fire. (De Inc. 56)It is against this background that we need to examine the claim that Athanasius teaches Penal Substitution. There is actually some level of merit to this claim, as long as you don't mind flexing your definition of PS a bit. Athanasius goes way beyond anything seen elsewhere in the Church Fathers in saying that Christ took on himself God's punishment toward us and exhausted it. He uses plenty of substitutionary language about Christ as our substitute, exhausting the power of the penalty against us in himself.
But... he places all of this penal substitutionary talk into his Recapitulation paradigm. The penalty that gets substituted is non-existence (not hell, like in modern PS). For Athanasius the problem of non-existence is solved by Jesus in a way that combines Recapitulation and penal substitution. Although, perhaps a better phrase would be "attempted penal participation" as he sees Christ trying to suffer the same punishment we do and in trying to participate in our punishment destroying the punishment itself as a result, rather than suffering it instead of us. An apt and amusing analogy, given Athanasius' logic, would be if an Elephant committed a crime so the police put it in jail and being too big to fit in the jail the Elephant burst all the cell walls and thus the jail was destroyed and no humans could ever be put in it again. According to Athanasius, Christ tries to take on man's punishment of death, but since he is Life Itself, death gets obliterated in the course of him trying to die. This penal particpation and recapitulation of Christ is universally effective - all mankind is saved from non-existence as a result, and we don't need to know about it or have faith in it or relying on it for it to be effective for us. It also has nothing directly to do with the final judgment (apart from allowing there to be one).
So, yes, penal substitutionary stuff is there in Athanasius's writing in a way, but it's conceived as a solution to an entirely different problem to what it's seen today as solving. If we limit our focus to "how does a human pass God's final judgment and go to heaven rather than hell" rather than "what did Christ in general achieve", then penal substitutionary thinking is not present in Athanasius'. Getting to heaven in his view is achieved by virtue which is achieved by following Christ's teachings.
So I would not say "Athanasius teaches penal substitution" without qualifying my statement heavily. What he teaches looks nothing much like the PS we are familiar with... it works quite differently as a solution to an entirely different problem, and has no relation to the criteria by which we go to heaven or hell. In this sense, "Athanasius does not teach the Penal Substitutionary model of the atonement" would be a far more accurate general statement. The authors of Pierced For Our Transgressions however hold Athanasius up as one of their best and most important proofs of the Fathers teaching their view of Penal Substitution...