'Purification' in the Bible

“If someone suddenly dies near him, defiling his consecrated head of hair, he must shave his head on the day of his purification; he is to shave it on the seventh day.

This is what you must do to them for their purification: Sprinkle them with the purification water. Have them shave their entire bodies and wash their clothes, and so purify themselves.

For the purification of the unclean person, they are to take some of the ashes of the burnt sin offering, put them in a jar, and add fresh water to them.

everything that can withstand fire—you are to pass through fire, and it will be clean. It must still be purified with the purification water. Anything that cannot withstand fire, pass through the water.