That shall not purify himself Shall contemptuously refuse to submit to this way of purification. Shall wash his clothes Because he is unclean. It is strange, that the same water should cleanse one person, and defile another. But God would have it so, to teach us that it did not cleanse by any virtue in itself, or in the work done, but only by virtue of God's appointment; and to show that the efficacy of God's ordinances doth not depend upon the person or quality of his ministers, because the same person who was polluted himself could and did, in the use of God's appointed means, cleanse others. He that toucheth the water Either by sprinkling of it, or by being sprinkled with it; for even he that was cleansed by it was not fully cleansed as soon as he was sprinkled, but only at the even of that day.
Related Commentaries of Numbers 19:20
Numbers 19:20-21
20 But the man that shall be unclean, and shall not purify himself, that soul shall be cut off from among the congregation, because he hath defiled the sanctuary of the LORD: the water of separation hath not been sprinkled upon him; he is unclean.
21 And it shall be a perpetual statute unto them, that he that sprinkleth the water of separation shall wash his clothes; and he that toucheth the water of separation shall be unclean until even.