In ancient Israel and Judah, a priest was an official who was set apart from the community in order to carry out certain religious duties and who served as intermediary between God and the community. Priests conducted sacrifices and rituals at holy places throughout the land (e.g., the shrine at Shiloh, north of Bethel in Canaan, see Judges 18:31; 21:19) and eventually in the temple in Jerusalem. They also instructed the people in the laws and traditions of Israel.
In post-exilic Judah, men who claimed descent from Aaron or Zadok were the mainline priests, whereas the Levites took up the subordinate roles. This may have been the final result of a conflict for power between these two groups of priests.