Moses Asks How the Corpse-Defiled Are Purified by the Red Heifer

[Another interpretation (of Ecclesiastes 8:1): "Who is like the wise person?" This is Moses, of whom it is written (Proverbs 21:22): "A wise man scaled the city of the mighty." "And who knows the interpretation of a matter?" — for he interpreted the Torah for Israel. "A person's wisdom lights up his face."] Rabbi Joshua of Sikhnin said in the name of Rabbi Levi: Concerning each and every matter that the Holy One, blessed be He, would say to Moses, He would tell him its uncleanness and its purification. When He reached the section "Speak unto the priests" (Leviticus 21), Moses said before Him: Master of the Universe, and if he becomes unclean, by what means is his purification? And He did not answer him. At that hour the face of Moses turned pale. This is what is written: "And the strength of his face is changed." And when He reached the section of the Heifer, the Holy One, blessed be He, said to him: Moses, that saying which I said to you, "Go, speak unto the priests," and you said to Me, "If he becomes unclean, by what means shall his purification be?", and I did not answer you — this is his purification: "And they shall take for the unclean person from the ashes of the burning of the sin-offering" (Numbers 19:17).