Mesopotamian religion begins from the fact that each city belonged to a god. Nippur was Enlil's, Uruk was Inanna's and An's, Eridu was Enki's, Ur was Nanna's, and the temple was the god's house in a literal sense, with a household, a table, an estate and dependants. Nicole Brisch's survey shows the pantheon working as a divine assembly that decides, quarrels and delegates, with a functioning bureaucracy of lesser gods beneath it.
Humanity's place in that arrangement is stated plainly in the creation narratives Stephanie Dalley translates. People were made so that the gods might rest from digging the canals. Service is therefore the point, and the flood story, preserved in the Atrahasis poem and again in Gilgamesh, turns on the gods' irritation at the noise their servants make.
Personal religion sat below the state cult. A person had a personal god who acted as advocate and whose withdrawal left them exposed, and the incantation collections address the illnesses, curses and ghosts that follow from such exposure. Francesca Rochberg's work shows how divination bound the two levels together, since the same reading of a liver, a star or a birth omen served both a king's campaign and a household's decision.