And if ye offer a sacrifice. — From Leviticus 17:3-7, it will be seen that the Israelites were in the habit of sacrificing to idols the animals intended for private consumption, and that this practice gave rise to the enactment that when any of the three kinds of quadrupeds are to be slaughtered for daily meat, they should first be devoted to God as peace-offerings. Hence the transition here from the prohibition of idolatrous worship to the peace-offerings. The simple abstention from sacrifice to idols and offering them to God is not enough. If the Israelites bring a peace-offering to the Lord it must be offered in the prescribed manner.
Ye shall offer it at your own will. — Better, ye shall offer it for your acceptance (see Leviticus 1:3), that is, ye are to do it in such a manner as will secure for you the Divine acceptance.