Numbers 16:5, 40

Then he said to Korah and his followers, “Tomorrow morning the LORD will show us who belongs to him and who is holy. The LORD will allow only those whom he selects to enter his own presence.

This would warn the Israelites that no unauthorized person—no one who was not a descendant of Aaron—should ever enter the LORD’s presence to burn incense. If anyone did, the same thing would happen to him as happened to Korah and his followers. So the LORD’s instructions to Moses were carried out.