Many of the OT stories are just rewrites of much earlier Sumerian/Babylonian/Mesopotamian myth.
The Genesis creation myth has great similarities to the Babylonian creation myth, the Enuma Elish.
Humans are also formed out of dirt or clay in the Mesopotamian stories.
The Garden of Eden = Edin in a Sumerian creation myth. The Sumerian story also includes the eating of a forbidden plant which brings down a curse and a "rib woman", Ninti.
Wiki also says about the Epic of Gilgamesh: "The parallels between the stories of Enkidu/Shamhat and Adam/Eve have been long recognized by scholars.
[20] In both, a man is created from the soil by a god, and lives in a natural setting amongst the animals. He is introduced to a woman who tempts him. In both stories the man accepts food from the woman, covers his nakedness, and must leave his former realm, unable to return. The presence of a snake that steals a plant of immortality from the hero later in the epic is another point of similarity."
Noah = Atra-Hasis in the Mesopotamian accounts. The rainbow is also given an explanation similar to the one in the Genesis account, where it's the necklace of the Goddess, Ishtar and serves as a reminder for her not to forget the Flood. There's a Greek story where Zeus floods the Earth, wiping out humanity due to our wicknessnes, but Prometheus saves a man and a woman by putting them on a boat.
Moses' childhood story is lifted from King Sargon of Akkad's story.
Moses being given the stone tablets from God is lifted from the story of the Sun God, Shamash, handing down the law to Hammurabi while atop a ziggurat. (Much of the Mosaic Law was based on or even lifted from the Code of Hammurabi.)
There's other stories that were taken from earlier Pagan myths, such as Samson, Abraham and Isaac and some of the Psalms were originally written for Baal. I could go on.
So Jews and Christians believe in Pagan myths and accept them as the word of their god. Go figure. It's really quite funny.