Traditional ancient stories such as the Fall of Man and the Great Flood were originally conceived and written down in Sumer, translated and modified later in Babylon, and reworked by the Assyrians before they were used by the Hebrew scribes for the versions which appear in the Bible. Although the basic paradigm of the biblical narratives and the Mesopotamian stories align closely, there are still significant differences as noted by scholar Stephen Bertman.
From Old-Babylonian (1900 bc) Enuma Elish (Not Sumerian) Is where we get written account of the god called Marduk that was a Babylonian god, also the creation-explanation. Enuma Elish doesn't come from Sumer 4-3000 bc or whatever, it comes from Babylon. So again the writings are actually established at a younger date than what we interpret, just like Aleister Crowley had said in his writings, only he made a metaphor of it and in context was not directly referring to the scriptures but this is what he meant. That the scriptures are younger than what we make them and an entire religion has been based on these writings that people don't really understand. "You Samarians worship what you don't understand."
Abraham (Actually Abram) is the patriarch ancestor noted in the Torah, Genesis or Bereshit. that god called upon to leave the city of Ur of the Chaldeans which is referring to Ur Kasdim. So Ur had it's time as an important port city of the Sumerians and as one of the earliest Nation-States right along with Eridu and Uruk, but also had it's decline in which the traditional time frame of the bible lines-up with Abrams departure of Ur. Later on in the book of Daniel there is reference to the lands in which they were exiled in, which is Babylon, was the lands of their ancestors. So if you look at all of this in it's proper context and timeline you see a different thing going on with god being something that predates Hebrews and seems to have been well established during the times of polytheism for example like Ashur or the Anu that were gods that created everything including other gods. Where it is that the Greeks and other polytheists differed like Hinduism was in that there were gods that created the gods that created the gods, on and on you see.