Leviticus begins with the people of Israel at the foot of Mount Sinai. The glory of the Lord had just filled the tabernacle (Ex. 40:34–38) and God now tells Moses to instruct the Levitical priests and the people of Israel concerning sacrifices, worship, the priesthood, ceremonial cleanness, the Day of Atonement, feasts and holy days, and the Year of Jubilee. The central message is that God is holy and he requires his people to be holy. The book also shows that God graciously provides atonement for sin through the shedding of blood. Traditionally, Jews and Christians recognize Moses as the author, writing sometime after the giving of the Law.