15 Eat the meat from the Peace-Offering of thanksgiving the same day it is offered. Don't leave any of it overnight. 16 "If the offering is a Votive-Offering or a Freewill-Offering, it may be eaten the same day it is sacrificed and whatever is left over on the next day may also be eaten. 17 But any meat from the sacrifice that is left to the third day must be burned up. 18 If any of the meat from the Peace-Offering is eaten on the third day, the person who has brought it will not be accepted. It won't benefit him a bit - it has become defiled meat. And whoever eats it must take responsibility for his iniquity.
Matthew Henry's Commentary on Leviticus 7:15-18
Commentary on Leviticus 7:11-27
(Read Leviticus 7:11-27)
As to the peace-offerings, in the expression of their sense of mercy, God left them more at liberty, than in the expression of their sense of sin; that their sacrifices, being free-will offerings, might be the more acceptable, while, by obliging them to bring the sacrifices of atonement, God shows the necessity of the great Propitiation. The main reason why blood was forbidden of old, was because the Lord had appointed blood for an atonement. This use, being figurative, had its end in Christ, who by his death and blood-shedding caused the sacrifices to cease. Therefore this law is not now in force on believers.