Leviticus 22:18

Speak unto Aaron, and to his sons
The priests, whose work it was to offer sacrifices, and therefore it behoved them to know what kind and sort were to be offered by them, when brought to them: and unto all the children of Israel:
who were to bring the sacrifices, and for whom they were to be offered, and therefore should be acquainted with the nature and kind of what would be acceptable to God, and what not: and say unto them, whatsoever [he be] of the house of Israel;
this phrase includes women and servants, and even Gentiles, as say the Jewish writers ^F17, who may vow vows, and make voluntary gifts, as well as the Israelites: or of the strangers in Israel:
those of other nations that dwelt there, either proselytes of the gate, or proselytes of righteousness, so Ben Gersom; and Aben Ezra observes, that the text speaks of the stranger, because there is some reason in the vows and freewill offerings of an Israelite and stranger, as follows: that will offer his oblation for all his vows, and for all his freewill
offerings, which they will offer unto the Lord for a burnt offering;
the wise men, as Aben Ezra observes, distinguish between a vow and a freewill offering; every vow is a freewill offering, but every freewill offering is not a vow; and though these were both of them sorts of peace offerings, yet they were not received from Gentiles under that notion, but as burnt offerings, because they were offered in devotion to God, and not to be eaten by Israelites; so Maimonides ^F18 says, they do not receive from Gentiles but burnt offerings only, as it is said ( Leviticus 22:25 ) , "neither from a stranger's hand" even burnt offerings of fowls they receive from a Gentile, though he be an idolater; but they do not receive of them peace offerings, nor meat offerings, nor sin offerings, nor trespass offerings; and so burnt offerings, which do not come by way of a vow, or a freewill offering, they do not receive from Gentiles, as the burnt offering of a new mother and the like unto it; a Gentile that brings peace offerings, they offer them as burnt offerings, because the heart of the Gentile is towards heaven.