THE LEVITES BECOME PRIESTS

Midrash Rabbah - Numbers 4:8

TAKE THE LEVITES, etc. (Numbers 3:45).

Similarly, when Moses had sacrifices offered at Sinai it was the firstborn who offered them; as it says: And he sent the young men of the children of Israel, who offered burnt-offerings, and sacrificed peace-offerings (Exodus 24:5). What is the meaning of ‘the young men’? The youths among the firstborn. ‘Who offered burnt-offerings’: From here you learn that no man offered sacrifices except the firstborn.

Now when Israel committed that unnameable act they said, ‘Let the firstborn come and offer sacrifices to it’; as it says: And they rose up early on the morrow, and offered burnt-offerings, and brought peace-offerings (Ex 32:6).