Numbers 19:9-10

19:9 “‘Then a man who is ceremonially clean must gather up the ashes of the red heifer and put them in a ceremonially clean place outside the camp. They must be kept for the community of the Israelites for use in the water of purification – it is a purification for sin. 19:10 The one who gathers the ashes of the heifer must wash his clothes and be ceremonially unclean until evening. This will be a permanent ordinance both for the Israelites and the resident foreigner who lives among them.

Numbers 19:13

19:13 Anyone who touches the corpse of any dead person and does not purify himself defiles the tabernacle of the Lord. And that person must be cut off from Israel, because the water of purification was not sprinkled on him. He will be unclean; his uncleanness remains on him.

Numbers 19:17-19

19:17 “‘For a ceremonially unclean person you must take some of the ashes of the heifer burnt for purification from sin and pour fresh running water over them in a vessel. 19:18 Then a ceremonially clean person must take hyssop, dip it in the water, and sprinkle it on the tent, on all its furnishings, and on the people who were there, or on the one who touched a bone, or one killed, or one who died, or a grave. 19:19 And the clean person must sprinkle the unclean on the third day and on the seventh day; and on the seventh day he must purify him, and then he must wash his clothes, and bathe in water, and he will be clean in the evening.

Psalms 51:7

51:7 Sprinkle me with water and I will be pure;

wash me and I will be whiter than snow.

Hebrews 9:13

9:13 For if the blood of goats and bulls and the ashes of a young cow sprinkled on those who are defiled consecrated them and provided ritual purity,