Exodus

He shall put on the holy linen coat, and he shall have the linen breeches upon his flesh, and shall be girded with a linen girdle, and with the linen mitre shall he be attired: these are holy garments; therefore shall he wash his flesh in water, and so put them on.

I will wash mine hands in innocency: so will I compass thine altar, O Lord:

Seven days shall ye eat unleavened bread; even the first day ye shall put away leaven out of your houses: for whosoever eateth leavened bread from the first day until the seventh day, that soul shall be cut off from Israel.

And the Lord spake unto Moses after the death of the two sons of Aaron, when they offered before the Lord, and died;

And the Lord said unto Moses, Speak unto Aaron thy brother, that he come not at all times into the holy place within the vail before the mercy seat, which is upon the ark; that he die not: for I will appear in the cloud upon the mercy seat.