Leviticus 22:21

“And whosoever offereth a sacrifice of peace offering unto the Lord, etc.] This, as Ben Gersom observes, is distinguished from a burnt offering; for though it was to be perfect, and without blemish, yet not obliged to be a male as that, (<030301>Leviticus 3:1). This was either by way of thanksgiving for mercies received, (<030712>Leviticus 7:12), or to accomplish [his] vow; made in any distress, that if God would deliver him, then he would offer such a sacrifice: or a freewill offering; either on account of favours received, or in order to obtain them: which sacrifice, whether in beeves or sheep; whether in bullocks or sheep, under which are comprehended goats, both being of the flock,…”

“22:21 A peace offering could function in several ways: as a thanksgiving offering, an offering to fulfill a vow, or a voluntary offering (see 3:1-17).”

“peace: Lev 3:1, Lev 3:6, 7:11-38 to accomplish: Gen 28:20, Gen 35:1-3; Num 15:3, Num 15:8; Deu 23:21-23; Psa 50:14; Pro 7:14; Ecc 5:4, Ecc 5:5 sheep: or, goats it shall be perfect: This law is so founded on the nature of the thing itself, that it has been in force among all nations that sacrificed victims to their deities. Leviticus 22:22”

“Every peace-offering was also to be faultless, whether brought "to fulfil a special (important) vow" (cf. Num 15:3, Num 15:8 : פּלּא, from פּלא to be great, distinguished, wonderful), or as a freewill gift; that is to say, it was to be free from such faults as blindness, or a broken limb (from lameness therefore: Deu 15:21), or cutting (i.e., mutilation, answering to חרוּם Lev 21:18), or an abscess (יבּלת, from יבל to flow, probably a flowing suppurating abscess). Leviticus 22:23”