“Upon them, therefore, upon men who, as animals were essentially impermanent, He bestowed a grace which other creatures lacked — namely, the impress of His own Image, a share in the reasonable being of the very Word Himself, so that, reflecting Him and themselves becoming reasonable and expressing the Mind of God even as he does, though in limited degree, they might continue for ever in the blessed and only true life of the saints in paradise. But since the will of man could turn either way, God secured this grace that He had given by making it conditional from the first upon two things — namely, a law and a place. He set them in His own paradise, and laid upon them a single prohibition. If they guarded the grace and retained the loveliness of their original innocence, then the life of paradise would be theirs, without sorrow, pain or care, and after it the assurance of immortality in heaven. (1.3)… God had not only made them out of nothing, but had also graciously bestowed on them His own life by the grace of the Word…the grace of their union with the Word made them capable of escaping from the natural law [i.e. death] provided that they retained the beauty of innocence with which they were created. (1.5)”
Just briefly, notice how clearly Athanasius affirms that God bestowed all kinds of grace on Adam in the garden prior to the Fall. The image of God is called “mercy” in another place and here he continues to emphasize this gracious relationship. Secondly, I find it interesting that Athanasius refers to humanity as being in “union with the Word.” Of course the Pauline literature is full of union with Christ motifs, and here Athanasius clearly understands our first parents’ state as being essentially the same. It appears that this union is primarily the means by which mortality/impermanence is held at bay in humanity but the transgression of God’s law breaks this union (covenant?) and thereby leaves death to work havoc in the sons and daughters of Adam.