When Moses saw that "there was wrath gone out from the Lord, and the plague was begun," he called Aaron to him, saying: "Take thy censer and put fire therein from off the altar, and lay incense thereon, and carry it quickly unto the congregation, and make atonement for them." This remedy against death Moses had learned from the Angel of Death himself at the time he was staying in heaven to receive the Torah.
At that time he had received a gift from each one of the angels, and that of the Angel of Death had been the revelation of the secret that incense can hold him at bay. Moses, in applying this remedy, had in mind also the purpose of showing the people the injustice of their superstition concerning the offering of incense. They called it death-bearing because it had brought death upon Nadab and Abihu, as well as upon the two hundred and fifty followers of Korah.
He now wished to convince them that it was this very incense that prevented the plague, and to teach them that it is sin that brings death. Aaron, however, did not know why he employed incense, and therefore said to Moses: "O my lord Moses, hast thou perchance my death in view? My sons were burned because they put strange fires into the censers. Shall I now fetch holy fire from the altar and carry it outside?
Surely I shall meet death through this fire!" Moses replied: "Go quickly and do as I have bidden thee, for while thou dost stand and talk, they die." Aaron hastened to carry out the command given to him, saying: "Even if it be my death, I obey gladly if I can only serve Israel thereby."