Numbers 16:5, 40

and he said to Korah and all his company, “In the morning the LORD will show who is his, and who is holy, and will bring him near to him. The one whom he chooses he will bring near to him.

to be a reminder to the people of Israel, so that no outsider, who is not of the descendants of Aaron, should draw near to burn incense before the LORD, lest he become like Korah and his company—as the LORD said to him through Moses.