If you want to be successful as a religion, you have to coopt aspects of other religions. In this case, the Hebrews used the Enuma Elish creation story, which was the popular creation story for that region, and then changed a little bit. The Genesis story is pretty much identical, except that God rested on the seventh day because He was tired. In the Enuma Elish, man was created in order that the creator gods could rest, meaning man was made as servants to the gods. The theological importance is that the Hebrews saw themselves as made in God's image, whereas those who believed in the Enuma Elish account saw themselves as servants to the gods.