The Priestly source (or simply P) is perhaps the most widely recognized of the sources underlying the Torah. It is both stylistically and theologically distinct from other material in the Torah, and includes a set of claims that are contradicted by non-Priestly passages and therefore uniquely characteristic: no sacrifice before the institution is ordained by Yahweh (God) at Sinai, the exalted status of Aaron and the priesthood, and the use of the divine title El Shaddai before God reveals his name to Moses, to name a few. In general, the Priestly work is concerned with priestly matters – ritual law, the origins of shrines and rituals, and genealogies – all expressed in a formal, repetitive style. It stresses the rules and rituals of worship, and the crucial role of priests, expanding considerably on the role given to Aaron (all Levites are priests, but according to P only the descendants of Aaron were to be allowed to officiate in the inner sanctuary). Background The history of exilic and post-exilic Judah is little known, but a summary of current theories can be made as follows: Religion in monarchic Judah centred around ritual sacrifice in the Temple. There, worship was in the hands of priests known as Zadokites (meaning that they traced their descent from an ancestor called Zadok, who, according to the Hebrew Bible, was the high priest appointed by Samuel.) There was also a lower order of religious officials called Levites, who were not permitted to perform sacrifices and were restricted to menial functions. While the Zadokites were the only priests in Jerusalem, there were other priests at other centres. One of the most important of these was a temple at Bethel, north of Jerusalem. Bethel, the centre of the "golden calf" cult, was one of the main religious centres of the northern kingdom of Israel and had royal support until Israel was destroyed by the Assyrians in 721 BCE. Aaron was in some way associated with Bethel. In 587 BCE the Babylonians conquered Jerusalem and took most of the Zadokite priesthood into exile, leaving behind the Levites, who were too poor and marginalised to represent a threat to their interests. The temple at Bethel now assumed a major role in the religious life of the inhabitants of Judah, and the non-Zadokite priests, under the influence of the Aaronite priests of Bethel, began calling themselves "sons of Aaron" to distinguish themselves