A Mesopotamian temple was not primarily a place of congregation. It was the house of a god, run as a great estate, and the god was present in it as a cult statue rather than merely symbolised by one.
The statue was made in a workshop and then, through rituals conventionally rendered as the washing and the opening of the mouth, separated from its manufacture and made able to eat, smell and act. Thereafter it was served: meals set before it and later removed for the king or the staff, clothing changed on a schedule, jewellery inventoried, transport arranged when it travelled to visit another god. Temple archives record the fields, herds, boats, weavers, brewers, bakers and scribes needed to sustain this, which made the major temples among the largest economic institutions in their cities.
The capture of a statue by an enemy was correspondingly serious, described as the god departing or being carried off, and its return was worth commemorating in an inscription. So was rebuilding. A king who restored a temple recorded that he had found the foundations laid by his predecessors and followed them exactly, and buried an inscription for whoever came after him.
Kings were the gods' stewards, chosen and sustained by them, and responsible for temples, canals, justice and defence. A few were treated as divine in their own right, the practice appears with the Akkadian ruler Naram-Sin and again under the Third Dynasty of Ur, but this was exceptional rather than normal, and the standard royal posture in the texts is one of service and of anxiety about whether that service has been accepted.
Public participation came mainly at festivals, above all the New Year rites at Babylon, in which the divine statues processed and the king underwent a ceremony of humiliation and reinstatement before Marduk.