Leviticus provides instruction on sacrifices and rituals for atonement of sins and purification. It establishes the priesthood to mediate between God and people. Several types of sacrifices are described including burnt offerings, grain offerings, peace offerings, and sin/guilt offerings to be offered on the altar to make atonement through the blood. The Day of Atonement in Leviticus 16 involved a special sacrifice and cleansing of the priest and sanctuary. Leviticus also covers laws of purity regarding clean and unclean things. The overall message is that sin separates us from God and sacrifices according to God's instructions are the means to pardon guilt and restore fellowship.