15 And the flesh of your thanksgiving sacrifice of well-being shall be eaten on the day it is offered; you shall not leave any of it until morning. 16 But if the sacrifice you offer is a votive offering or a freewill offering, it shall be eaten on the day that you offer your sacrifice, and what is left of it shall be eaten the next day; 17 but what is left of the flesh of the sacrifice shall be burned up on the third day. 18 If any of the flesh of your sacrifice of well-being is eaten on the third day, it shall not be acceptable, nor shall it be credited to the one who offers it; it shall be an abomination, and the one who eats of it shall incur guilt.
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.