He will teach Your ordinances … law: Besides performing priestly duties like sacrifices and assisting at the Tent of Meeting and the temple, the Levites were responsible for teaching the Torah (31:9–13).
set incense: Only Levitical priests could perform this ministry (Numbers 16:39–40). Later, when King Uzziah entered the temple to offer incense, he was strongly condemned. He was arrogant in violating what was only the privilege of the priests. He suffered from a skin disease for the rest of his life (2 Chronicles 26:16–21).