As the book of Exodus tells it, when the People of God was formed out of liberated slaves from Egypt (a kind of early Liberia), Aaron and his sons were made the first priests of the new community. Like all the peoples around them the Hebrews took it for granted that a real established society needed a priesthood, just as we take it for granted that a society needs some kind of civil service or some kind of school system. Aaron was the first high priest of the children of Israel, he had a job, an important job, within that community. The priest’s job was to arrange the transactions with the gods of the community, to ensure that the gods did not become hostile, for this could be disastrous for the people. The priest had to find out what the gods wanted and arrange for the people to give it to them. So he stood as mediator, on the frontier, looking both ways, to the gods and to the people; communicating to the people the messages of the gods, communicating to the gods the offerings of the people.

But, of course, the Children of Israel were no ordinary society, they were something unique in human history; they made a gradual but huge revolution from which all subsequent humankind has benefited and (as with all revolutions) suffered too. For by the time the Book of Exodus was put together it was becoming clear that their God was not one (or more) of the gods, and this was going to make a difference to what such things as priesthood meant.