Leviticus 16:24
"And he shall wash his flesh with water in the holy place, and put on his garments, and come forth, and offer his burnt offering, and the burnt offering of the people, and make an atonement for himself, and for the people."
Cross References (ranked by relevance)
Leviticus 14:9
But it shall be on the seventh day, that he shall shave all his hair off his head and his beard and his eyebrows, even all his hair he shall shave off: and he shall wash his clothes, also he shall wash his flesh in water, and he shall be clean.
Hebrews 9:10
Which stood only in meats and drinks, and divers washings, and carnal ordinances, imposed on them until the time of reformation.
Leviticus 22:6
The soul which hath touched any such shall be unclean until even, and shall not eat of the holy things, unless he wash his flesh with water.