For the purification of the unclean person, take some of the ashes of the burnt sin offering, put them in a jar, and pour fresh water over them.

Hebrews 9:13
For if the blood of goats and bulls and the ashes of a heifer sprinkled on those who are ceremonially unclean sanctify them so that their bodies are clean,

Numbers 19:9
Then a man who is ceremonially clean is to gather up the ashes of the heifer and store them in a ceremonially clean place outside the camp. They must be kept by the congregation of Israel for preparing the water of purification; this is for purification from sin.

Numbers 19:18
Then a man who is ceremonially clean is to take some hyssop, dip it in the water, and sprinkle the tent, all the furnishings, and the people who were there. He is also to sprinkle the one who touched a bone, a grave, or a person who has died or been slain.

Numbers 31:23
everything that can withstand the fire--must be put through the fire, and it will be clean. But it must still be purified with the water of purification. And everything that cannot withstand the fire must pass through the water.

Ezekiel 36:25
I will also sprinkle clean water on you, and you will be clean. I will cleanse you from all your impurities and all your idols.

Zechariah 13:1
"On that day a fountain will be opened to the house of David and the people of Jerusalem, to cleanse them from sin and impurity.

And for an unclean person they shall take of the ashes of the burnt heifer of purification for sin, and running water shall be put thereto in a vessel: