Immortality: Most simply, the inability to cease to exist or the ability to exist eternally. In this sense God is the only being who is truly immortal, because God has always existed and will not cease to exist. Some theologians argue, however, that human souls are created by God as intrinsically immortal, whereas others argue that the soul only becomes extrinsically immortal upon the reception of “eternal life” through salvation. Either way, it is commonly agreed that all humans, whether righteous or wicked, are subject to physical death as a consequence of sin and thus are universally mortal as to their earthly life. Whatever immortality humans possess is due to the will and power of God.1
1. Stanley J. Grenz, David Guretzki & Cherith Fee Nordling, Pocket Dictionary of Theological Terms (Downers Grove, IL: InterVarsity Press, 1999), p. 64.