Deuteronomy 21:6; Deuteronomy 23:11

Deuteronomy 21:6

6 "All the elders of that city which is nearest to the slain man shall wash their hands over the heifer whose neck was broken in the valley;

Deuteronomy 23:11

11 "But it shall be when evening approaches, he shall bathe himself with water, and at sundown he may reenter the camp.