The ultimate source of all law being the deity himself, the
original legal tribunal was the place where the image or
symbol of the god stood. A legal decision was an oracle or
omen, indicative of the will of the god. The power thus
lodged in the priests of Babylonia and Assyria was enormous.
They virtually held in their hands the life and death of the
people.

And of the business side of this vast religious system:

The temples were the natural depositories of the legal
archives, which in the course of centuries grew to veritably
enormous proportions. Records were made of all decisions;
the facts were set forth, and duly attested by witnesses.
Business and marriage contracts, loans and deeds of sale
were in like manner drawn up in the presence of official
scribes, who were also priests. In this way all commercial
transactions received the written sanction of the religious
organization. The temples themselves--at least in the large
centres--entered into business relations with the populace.
In order to maintain the large household represented by such
an organization as that of the temple of Enlil of Nippur,
that of Ningirsu at Lagash, that of Marduk at Babylon, or
that of Shamash at Sippar, large holdings of land were
required which, cultivated by agents for the priests, or
farmed out with stipulations for a goodly share of the
produce, secured an income for the maintenance of the temple
officials. The enterprise of the temples was expanded to the
furnishing of loans at interest--in later periods, at