Moses
Leviticus 9:12ESV·traditional attribution

Then he killed the burnt offering, and Aaron’s sons handed him the blood, and he threw it against the sides of the altar.

Matthew Henry Presbyterian @wholebiblehenry

These being the first offerings that ever were offered by the levitical priesthood, according to the newly-enacted law of sacrifices, the manner of offering them is particularly related, that it might appear how exactly they agreed with the institution. 1.

Commenting on Leviticus 9:8-22

John Gill Reformed Baptist @doctorgill

And they presented the burnt offering to him,.... After it was cut in pieces, as the ram of the burnt offering was by Moses, Lev 8:20 and so it was done to this, as appears by what follows: with the pieces thereof, and the head, and he burnt them upon the altar; the Septuagint version is, "he put them on the altar".

Keil & Delitzsch Lutheran @keilanddelitzsch

Lev 9:12-14 The burnt-offering was presented according to the general rule (Lev 1:3-9), as in Lev 8:18-21. המציא (Lev 9:12): to cause to attain; here, and in Lev 9:18, to present, hand over. לנתחיה, according to its pieces, into which the burnt-offering was divided (Lev 1:6), and which they offered to Aaron one by one. No meat-offering was connected with Aaron’s burnt-offerings, partly because the law contained in Num 15:2.

Commenting on Leviticus 9:12-14