At the beginning of Numbers, Israel prepares to continue the journey from Mount Sinai to the promised land. God devotes one of the twelve tribes, the Levites, to assist Aaron in the work of the priesthood, maintaining and watching over Israel's religious articles. After dedicating the Tabernacle, which houses the Ark of the Covenant, the Israelites leave Sinai, guided by the movements of a cloud that rests over the Tabernacle. Entering the desert, the people begin to complain about everything from the lack of interesting food to Moses's leadership.