1 Chronicles 23 · a question people ask
Why were Moses' sons Levites and not priests?
The chapter says who was set apart, not why Moses' line wasn't. "Aaron was separated that he should sanctify the most holy things, he and his sons forever" (23:13). "But as for Moses the man of God, his sons were named among the tribe of Levi" (23:14). This is how the Law had given it. The LORD told Moses, "Bring Aaron your brother, and his sons with him, near to you from among the children of Israel, that he may minister to me in the priest’s office" (Exodus 28:1), and "You shall appoint Aaron and his sons, and they shall keep their priesthood" (Numbers 3:10). Moses' sons, Gershom and Eliezer (23:15), are listed with the other families of Kohath (23:12-20). The Bible gives no reason beyond the LORD's word to Moses, and this answer doesn't add one.
The verses
“The sons of Amram: Aaron and Moses; and Aaron was separated that he should sanctify the most holy things, he and his sons forever, to burn incense before the LORD, to minister to him, and to bless in his name forever. But as for Moses the man of God, his sons were named among the tribe of Levi. The sons of Moses: Gershom and Eliezer.”
““Bring Aaron your brother, and his sons with him, near to you from among the children of Israel, that he may minister to me in the priest’s office: Aaron, with Nadab, Abihu, Eleazar, and Ithamar, Aaron’s sons.”
“You shall appoint Aaron and his sons, and they shall keep their priesthood, but the stranger who comes near shall be put to death.””