Thematic Bible: For those who had recently killed someone in battle

And ye must abide outside the camp seven days; and whoever has killed any person and whoever has touched any dead body ye shall remove the sin from them on the third and on the seventh day, both of yourselves and of your captives. Likewise remove all sin from all your clothing and all that is made of skins and all work of goats' hair and every vessel made of wood. And Eleazar, the priest, said unto the men of war which went to the battle, This is the ordinance of the law which the LORD commanded Moses; read more.
certainly the gold and the silver, the brass, the iron, the tin, and the lead, every thing that may endure the fire, ye shall cause to pass through the fire, and it shall be clean; nevertheless, ye shall remove the sin with the water of separation; and all that does not endure the fire ye shall cause to go through the water. Ye shall also wash your clothes on the seventh day, and ye shall be clean, and afterwards ye shall come into the camp.