15 And the flesh of the sacrifice of his peace offerings for thanksgiving shall be eaten on the day of his offering. He shall not leave any of it until the morning. 16 But if the sacrifice of his offering is a vow offering or a freewill offering, it shall be eaten on the day that he offers his sacrifice, and on the next day what remains of it shall be eaten. 17 But what remains of the flesh of the sacrifice on the third day shall be burned up with fire. 18 If any of the flesh of the sacrifice of his peace offering is eaten on the third day, he who offers it shall not be accepted, neither shall it be credited to him. It is tainted, and he who eats of it shall bear 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.