For Athanasius, the corruption due to sin is the forewarned expression of wrath for failure to adhere to the divine prohibition. The consequences were clearly detailed at the outset: eat from the tree and “dying ye shall die.” Had our first parents remained good, they would have kept “the life in paradise without sorrow or pain or care, besides having the promise of incorruption in heaven.” But humanity chose poorly, “incurring the corruption in death which was theirs by nature.” Because of sin, humanity forfeited the opportunity to be freed from the limitations of mutability and corruptibility inherent with human nature. In choosing to turn away from the contemplation of the divine and chase after carnal, earthly knowledge, man was punitively “released” to that which he chose—carnality and corruptibility. God would no longer stand in the way of humanity’s ontological proclivity toward corruption and non-being. As a result, death, “gained from that time forth a legal hold over us, and it was impossible to evade the law, since it had been laid down by God because of the transgression.”
In our discussion of the curse of sin as a “legal hold” over humanity, it will be helpful to note that Athanasius’ overall theology anticipates (and assumes) the later voluntarism of medieval soteriology. For Athanasius, the divine curse on sin does not flow of necessity from the nature of God; God’s nature as “just” does not require him to punish humanity for its act(s) of disobedience. Instead, the necessity of the curse flows out of God’s inability to lie. God said death would follow sin, and so it must come to pass. For Athanasius, sin has a legal hold over humanity only in as much as God has chosen to deal with humanity in this way. Had God not invoked the curse prior to Adam’s disobedience, there would have been no absolute legal necessity that Adam die.
More needs to be said on this, but the salient point to be made here is that Athanasius’ focus on “sin as curse” is not primarily about the judicial necessity of the curse, as much as it is about the ontological effects of the curse. Consequently, Athanasius’ understanding of Christ’s death—and the atonement at large—is more concerned with overcoming the corruption of the curse, than with balancing the scales of divine justice. As we will see below, both judicial release and ontological healing are accomplished through Christ’s death; but the emphasis is on the latter.
(All quotes are from Athanasius' On the Incarnation)