Athanasius on Penal Substitutionary Atonement

7. And having declared that he would become man, afterwards the Psalter also points to his passibility in the flesh. Perceiving, then that there would be a plot on the part of the Jews, it sings in Psalm 2, Wherefore did the heathen rage, and the nations imagine vain things? The kings of the earth stood up, and the rulers gathered themselves together against the Lord and against his Anoited. In the twenty-first it tells the manner of death from the Savior's own lips: ... you have brought me down to the dust of death. For many dogs have surrounded me; the assembly of the wicked has attacked me from all sides. They pierced my hands and feet. They counted all my bones. They divided my garments among themselves, and cast lots upon my raiment. When it speaks of the piercing of the hands and feet, what else than a cross does it signify? After teaching all these things, it adds that the Lord not for his own sake, but for ours. And it says again through his own lips in Psalm 87, Your wrath was pressed heavily upon me, and in Psalm 68, Then I restored which I did not take away. For although he was not himself obligated to give account for any crime, he died - but he suffered on our behalf, and he took on himself the wrath directed on us on account of the transgression, as it says in Isaiah, He took on our weaknesses. This is evident also when we say in Psalm 137, The Lord will recompense them on my behalf, and the Spirit says in the seventy-first, and he will save the children of the needy, and shall bring low the false accuser... for he has delivered the poor from the oppressor; and the laborer, who had no helper.

Athanasius, "A Letter to Marcellinus", The Life of Antony and the Letter to Marcellinus, Paulist Press, 1980, Page 105.