Numbers 16:44

40 just as the LORD commanded him through Moses. This was to be a reminder to the Israelites that no outsider who is not a descendant of Aaron should approach to offer incense before the LORD, lest he become like Korah and his followers.

41 The next day the whole congregation of Israel grumbled against Moses and Aaron, saying, “You have killed the LORD’s people!”

42 But when the congregation gathered against them, Moses and Aaron turned toward the Tent of Meeting, and suddenly the cloud covered it and the glory of the LORD appeared.

43 Then Moses and Aaron went to the front of the Tent of Meeting,

44 and the LORD said to Moses,

45 “Get away from this congregation so that I may consume them in an instant.” And Moses and Aaron fell facedown.

46 Moses said to Aaron, “Take your censer, place fire from the altar in it, and add incense. Go quickly to the congregation and make atonement for them, because wrath has come out from the LORD; the plague has begun.”

47 So Aaron took the censer as Moses had ordered and ran into the midst of the assembly. And seeing that the plague had begun among the people, he offered the incense and made atonement for the people.

48 He stood between the living and the dead, and the plague was halted.

Read all of Numbers 16