Moses
Leviticus 19:5ESV·traditional attribution

“When you offer a sacrifice of peace offerings to the LORD, you shall offer it so that you may be accepted.

Matthew Henry Presbyterian @wholebiblehenry

Moses is ordered to deliver the summary of the laws to all the congregation of the children of Israel (Lev 19:2); not to Aaron and his sons only, but to all the people, for they were all concerned to know their duty. Even in the darker ages of the law, that religion could not be of God which boasted of ignorance as its mother.

Commenting on Leviticus 19:1-10

John Gill Reformed Baptist @doctorgill

And if ye offer a sacrifice of peace offerings unto the Lord,.... Which were of three sorts, a thanksgiving, a vow, and a voluntary offering, Lev 7:11; the latter seems to be here meant, as appears by what follows: ye shall offer it at your own will; a voluntary freewill offering, of their own accord, and not by force, as Aben Ezra; and in such...

Jamieson-Fausset-Brown Reformed @jfbcommentary

if ye offer a sacrifice of peace offerings unto the Lord, ye shall offer it at your own will--Those which included thank offerings, or offerings made for vows, were always freewill offerings. Except the portions which, being waved and heaved, became the property of the priests (see Lev.