Numbers 19:14-16

14This is the law, when a man dieth in a tent: every one that cometh into the tent, and all that is in the tent, shall be unclean seven days.

15And every open vessel, which hath no covering bound upon it, shall be unclean.

16And every one that toucheth one that is slain with a sword in the open fields, or a dead person, or the bone of a man, or a grave, shall be unclean seven days.