Numbers 16:46-48

46So Moses said to Aaron, “Take a censer and put fire in it from the altar, put incense on it, and take it quickly to the congregation and make atonement for them; for wrath has gone out from the Lord. The plague has begun.”

47Then Aaron took it as Moses commanded, and ran into the midst of the assembly; and already the plague had begun among the people. So he put in the incense and made atonement for the people.

48And he stood between the dead and the living; so the plague was stopped.