The Passover
The Passover and Feast of Unleavened Bread were originally agricultural festivals denoting the arrival of spring. The sacrifice of a lamb at Passover was then associated [Exodus 12:1-13] with the Israelites in Egypt being “passed over”, i.e. spared, at the time of the death of the Egyptian first-born children. The implication is that this particular sacrifice was made once, and was then celebrated in the week-long feast of Unleavened Bread [Exodus 12: 14-20].
However, in a later strand of the tradition, the Passover sacrifice has become an annual event [Exodus 12: 24-27]. We are told that this was when the Israelites entered the Promised Land, but in fact it refers to a later time when the Temple existed in Jerusalem – with its priesthood – and the ritual was made regular and entrusted to priests.
The arrival of a priestly caste led to the priests ‘taking control’ of what had been simple, popular ceremonies. The sacrifice of a lamb replaced the sacrifice of a first-born male child (the Jews did not practise human sacrifice, unlike some of their pagan neighbours, as the story of Abraham and Isaac makes clear). But later, a priestly tradition ‘tightened up’ the rules and the offering of an animal began to apply for the first-born child of either gender [Leviticus 12: 7-8].
The earliest ceremonies involved bringing an animal for sacrifice, blessing it, and sharing it in a meal. But when priests appeared on the scene to regulate matters, the sacrifice became the be-all-and-end-all. Something similar happened in early Christianity, where the Eucharist was first celebrated in the context of a festive meal, but later, under priestly influence, the ‘meal part’ dropped out, leaving a stylised, sacred ritual.