Elsewhere in his writings, Athanasius describes the human predicament as a descent and fall back into non-existence. Without God, the created order is unstable and prone to fall back into nothingness. After the Fall, this was what was happening to humanity and the cosmos. We were, in the words of Athanasius, relapsing back into non-being and non-existence. We were dissolving and fading away.
Seeing creation falling into nothingness, God acts through the Incarnation, reuniting Word and Creation, to restabilize the cosmos to keep it from fading away. Athanasius:
For the nature of created things, having come into being from nothing, is unstable, and is weak and mortal when considered by itself...So seeing that all created nature according to its own definition is in a state of flux and dissolution, therefore to prevent this happening and the universe dissolving back into nothing, after making everything by his own eternal Word and bringing creation into existence, [God] did not abandon it to be carried away and suffer through its own nature, lest it run the risk of returning to nothing...lest it suffer what would happen...a relapse into non-existence, if it were not protected by the Word.