There is debate in the philosophy of religion about whether the being of God is timelessly eternal or is instead temporal but unbounded. In this paper, I seek to defend the first view by motivating and deriving it from the Christian doctrines of the trinity and salvation. My goal is to present the notion of eternity in a way that makes clear that it belongs to God by nature and to man by grace, with the condition of time being part of the medium of grace. To this end, I also employ the doctrine of theosis, as found in Maximus the Confessor and Dumitru Staniloae, and the Augustinean theory of time.