On the third day, and on the seventh day he shall be clean— See Numbers 19:19. Hence it appears, that this water of separation was designed chiefly for the purging of that great impurity contracted by touching a dead body.—We may also infer from this, that these ashes were kept in all the cities of Judea, where every person might easily have them to put into water, and be sprinkled with it, as they had occasion; for no priest was required to make this purification; but any clean person might sprinkle with it, Numbers 19:18-19.
Related Commentaries of Numbers 19:12
Numbers 19:12
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.