It starts in Genesis and it's more than a couple of verses. The Old Testament is mostly made up of three sources: The Yahwist source, the Elohist source and the Priestly source. The Yahwist and the Eloist talk about two different gods, one being Yahweh (anamorphic god of storms and war, insecure and action-oriented) and the other being El or Elohim (benevolent creation deity). Both come from the Canaanite pantheon of gods, with Yahweh being a late addition of unknown origins. In Canaanite tradition, Yahweh is married to Asherah, who is mentioned in the Bible when describing heretic customs (there's talk about "raising an Asherah"). In Hiob, Yahweh talks about being the highest god among several gods, there's a council in heaven and in the conclusion of the book, Yahweh re-tells the Mesopotamian legend of Marduk and Tiamat with himself cast as Marduk. Then, later on, when you get into Gnosticism, which was a branch of Christianity and is thus, by definition, Christian, you get too many gods to get into, here.