Midrash for Numbers 3:32

Moses introduced priestcraft, priesthood, sacrifice, and the law. He introduced priestcraft when he officiated as priest for seven days during the inauguration (of the priesthood); priesthood when He appointed Elazar the son of Aaron to the office of priest in the Temple, as it is said: And the chief over the princes of the Levites was Elazar the son of Aaron the priest (Num. 3:32); sacrifice, for it is said: And Moses made the whole head ram smoke upon the altar; it was a burnt offering (Lev. 8:20); and law, for it is written: And I will give to thee the tablets of stone and the law and the commandments (Exod. 24:12). Balaam instituted gambling, plaiting the hair, sorcery, and unchastity. Hence, Noah was one of four men who introduced four things.

Moses was first with the priesthood, with the pulpit, with the sacrifices, and with the Torah.
• [With the priesthood, when he served in the high priesthood for the seven days during the consecration (of Aaron and his sons.)]⁷³yYoma 1:1 (38b); Lev. R. 11:7; PRK 4:5; PR 14:11.
• With the pulpit, when he had Eleazar stand on the pulpit. Thus it is stated (in Numb. 3:32): AND THE PRINCE OF THE LEVITE PRINCES WAS ELEAZAR….⁷⁴As a Levite he would officiate from a pulpit.
• With the sacrifices: Where is it shown? (Lev. 8:21): MOSES SACRIFICED THE [WHOLE] RAM UPON THE ALTAR (during the consecration of Aaron and his sons).
• With the Torah: Where is it shown? Where it is stated (in Exod. 24:12): COME UP TO ME ON THE MOUNTAIN [AND BE THERE, AND I WILL GIVE YOU STONE TABLETS WITH TORAH AND THE COMMANDMENTS WHICH I HAVE WRITTEN FOR THEIR INSTRUCTION].