 As the topic is the God of Western theism, there are constraints arising from relevant passages in Western Scripture. Much of the discussion focuses on the Judeo-Christian, especially the Christian, tradition. (But note that specific Christian doctrines such as the doctrine of the Trinity or the Incarnation, while closely related, are not the focus here.) The Bible contains many passages calling God eternal, as well as ones that elaborate on God’s eternality. For example, there are passages telling us that God’s “years have no end” (Ps. 102:27, all quotations are from the New Revised Standard Version) and that God exists “from everlasting to everlasting” (Pss. 90:2, 103:17). God says, “let there be lights in the dome of the sky to separate the day from the night, and let them be for signs and for seasons and for days and years” (Gen. 1:14), and “I am the first and I am the last” (Isa. 44:6). Moreover, we are told that God promised us eternal life “before the ages began” (Titus 1:2), and that “He himself is before all things” (Col. 1:17). These passages require interpretation, and that’s where the philosophical work begins (see, e.g., Leftow 2005 for a formulation of constraints based on these passages).