Numbers 16:40

16:40 It was a memorial for the Israelites, that no outsider who is not a descendant of Aaron should approach to burn incense before the Lord, that he might not become like Korah and his company – just as the Lord had spoken by the authority of Moses.

Numbers 36:8

36:8 And every daughter who possesses an inheritance from any of the tribes of the Israelites must become the wife of a man from any family in her father’s tribe, so that every Israelite may retain the inheritance of his fathers.