Charles Ellicott Commentary 1 Samuel 15:22

"And Samuel said, Hath Jehovah as great delight in burnt-offerings and sacrifices, as in obeying the voice of Jehovah? Behold, to obey is better than sacrifice, and to hearken than the fat of rams." — 1 Samuel 15:22 (ASV)

Behold, to obey is better than sacrifice. — In this answer, it would seem that the Spirit of the Lord descended upon Samuel, and that he here uttered one of those rapt expressions which, now and again in the course of each of these Hebrew prophets’ lives, these famous men were commissioned by the Divine power to declare to their fellows. The words of Samuel here were reproduced, or at least referred to, by other prophets and teachers of the Old Covenant; for example, see Psalms 50:8-14; Psalms 51:16–17; Isaiah 1:11; Jeremiah 6:20; Micah 6:6–8; Hosea 6:6. Our Lord Himself, in His words recorded in Matthew 9:13, if not actually referring to this passage, makes substantially the same declaration.

Irenaeus, Haer. 4:32 (quoted by Wordsworth), sees in this great saying of Samuel’s a plain intimation that the day would come when the burnt offerings enjoined on Israel would give place to a simple worship of the heart. Wordsworth also quotes a weighty comment from St. Gregory (Moral. 35:10): “In sacrifices (per victimas) a man offers only strange flesh, whereas in obedience he offers his own will.”