Numbers 19:7

4 Then let Eleazar the priest take some of her blood on his finger, shaking the blood seven times in the direction of the front of the Tent of meeting:

5 And the cow is to be burned before him, her skin and her flesh and her blood and her waste are to be burned:

6 Then let the priest take cedar-wood and hyssop and red thread, and put them into the fire where the cow is burning.

7 And the priest, after washing his clothing and bathing his body in water, may come back to the tent-circle, and will be unclean till evening.

8 And he who does the burning is to have his clothing washed and his body bathed in water and be unclean till evening.

9 Then let a man who is clean take the dust of the burned cow and put it outside the tent-circle in a clean place, where it is to be kept for the children of Israel and used in making the water which takes away what is unclean: it is a sin-offering.

10 And he who takes up the dust of the burned cow is to have his clothing washed with water and be unclean till evening: this is to be a law for ever, for the children of Israel as well as for the man from another country who is living among them.