Discovery BoxNumbers 19:12 
Context19:12 He must purify himself 1 with water on the third day and on the seventh day, and so will be clean. But if he does not purify himself on the third day and the seventh day, then he will not be clean.
Numbers 19:19
Context19:19 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, 2 and then he must wash his clothes, and bathe in water, and he will be clean in the evening.
1 tn The verb is the Hitpael of חָטָא (khata’), a verb that normally means “to sin.” But the Piel idea in many places is “to cleanse; to purify.” This may be explained as a privative use (“to un-sin” someone, meaning cleanse) or denominative (“make a sin offering for someone”). It is surely connected to the purification offering, and so a sense of purify is what is wanted here.
2 tn The construction uses a simple Piel of חָטָא (khata’, “to purify”) with a pronominal suffix – “he shall purify him.” Some commentators take this to mean that after he sprinkles the unclean then he must purify himself. But that would not be the most natural way to read this form.
