"Hence he was in the shadow of life, whereas sinners are in the shadow of death. According to Isaiah, the people who sinned sat in the shadow of death. For these a light arose, not by the merits of their virtues but by the grace of God. There is no distinction, therefore, between the breath of God and the food of the tree of life. No one can say that he can acquire more by his own efforts than what is granted him by the generosity of God."
St. Ambrose of Milan, On Paradise, 5.29