The man who is ceremonially clean is to sprinkle the unclean person on the third day and on the seventh day. After he purifies the unclean person on the seventh day, the one being cleansed must wash his clothes and bathe in water, and that evening he will be clean.
Directions are here given concerning the use and application of the ashes which were prepared for purification. they were laid up to be laid out; and therefore, though now one place would serve to keep them in, while all Israel lay so closely encamped, yet it is probable that afterwards, when they came to Canaan, some of these ashes were kept in every town, for...
Commenting on Numbers 19:11-22
And the clean person shall sprinkle upon the unclean,.... The clean priest shall sprinkle upon the unclean man, as the Targum of Jonathan; that is, he shall sprinkle the water of purification upon him that is unclean in any of the above ways: on the third day, and on the seventh day; See Gill on Num 19:12, and on the seventh day he shall purify...
And the clean [person] shall sprinkle upon the unclean on the third day, and on the seventh day: and on the seventh day he shall purify himself, and wash his clothes, and bathe himself in water, and shall be clean at even. (l) Because he had been among them that were unclean: or else had touched the water as in .