Num 19:2-9

This is the ordinance of the law which the LORD hath commanded, saying, Speak unto the children of Israel, that they bring thee a red heifer without spot, wherein is no blemish, and upon which never came yoke:

And ye shall give her unto Eleazar the priest, that he may bring her forth without the camp, and one shall slay her before his face:

And Eleazar the priest shall take of her blood with his finger, and sprinkle of her blood directly before the tabernacle of the congregation seven times:

And one shall burn the heifer in his sight; her skin, and her flesh, and her blood, with her dung, shall he burn:

And the priest shall take cedar wood, and hyssop, and scarlet, and cast it into the midst of the burning of the heifer.

Then the priest shall wash his clothes, and he shall bathe his flesh in water, and afterward he shall come into the camp, and the priest shall be unclean until the even.

And he that burneth her shall wash his clothes in water, and bathe his flesh in water, and shall be unclean until the even.

And a man that is clean shall gather up the ashes of the heifer, and lay them up without the camp in a clean place, and it shall be kept for the congregation of the children of Israel for a water of separation: it is a purification for sin.