Numbers 19:14

"This is the law when a man dieth in a tent: everyone that cometh into the tent, and every one that is in the tent, shall be unclean seven days. And every open vessel, which hath no covering bound upon it, is unclean. And whosoever in the open field toucheth one that is slain with the sword, or a dead body, or a bone of a man, or a grave, shall be unclean seven days. And for the unclean they shall take of the ashes of the burning of the sin-offering; and running water shall be put thereto in a vessel: and a clean person shall take hyssop, and dip it in the water, and sprinkle it upon the tent, and upon all the vessels, and upon the persons that were there, and upon him that touched the bone, or the slain, or the dead, or the grave: and the clean person shall sprinkle upon the unclean on the third day, and on the seventh day: and on the seventh day he shall purify him; and he shall wash his clothes, and bathe himself in water, and shall be clean at even."

"When a man dieth in a tent ..." (Numbers 19:14). This does not restrict the legislation to tent-dwellers, being rather a reflection of the wilderness habitation of Israel when the law was given. "The LXX has `house' here instead of tent, and it appears that the law was transferred without modification from tent-dwellers to house-dwellers."[14]

Numbers 19:16 includes the bones, and presumably any other human relics, as well as graves as sources of uncleanness. It was from this that the Pharisees of Jesus' day whitewashed all the graves to prevent one's accidentally incurring uncleanness by unintentionally touching, or walking over one.

"And the clean person ..." (Numbers 19:19). Note that the priests were not even necessary in the cleansing ceremonies connected with the whole house (Matthew 23:7).