NET
12 He must purify himself 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.
Darby
12 He shall purify himself with it on the third day, and on the seventh day he shall be clean; but if he purify not himself the third day, then the seventh day he shall not be clean.
KJV
12 He shall purify himself with it on the third day, and on the seventh day he shall be clean: but if he purify not himself the third day, then the seventh day he shall not be clean.