Wherefore then didst thou not obey the voice of the LORD, but didst fly upon the spoil, and didst evil in the sight of the LORD?

Matthew Henry's Concise Commentary

15:10-23 Repentance in God is not a change of mind, as it is in us, but a change of method. The change was in Saul; He is turned back from following me. Hereby he made God his enemy. Samuel spent a whole night in pleading for Saul. The rejection of sinners is the grief of believers: God delights not in their death, nor should we. Saul boasts to Samuel of his obedience. Thus sinners think, by justifying themselves, to escape being judged of the Lord. The noise the cattle made, like the rust of the silver, Jas 5:3, witnessed against him. Many boast of obedience to the command of God; but what means then their indulgence of the flesh, their love of the world, their angry and unkind spirit, and their neglect of holy duties, which witness against them? See of what evil covetousness is the root; and see what is the sinfulness of sin, and notice that in it which above any thing else makes it evil in the sight of the Lord; it is disobedience: Thou didst not obey the voice of the Lord. Carnal, deceitful hearts, like Saul, think to excuse themselves from God's commandments by what pleases themselves. It is hard to convince the children of disobedience. But humble, sincere, and conscientious obedience to the will of God, is more pleasing and acceptable to him than all burnt-offering and sacrifices. God is more glorified and self more denied, by obedience than by sacrifice. It is much easier to bring a bullock or lamb to be burned upon the altar, than to bring every high thought into obedience to God, and to make our will subject to his will. Those are unfit and unworthy to rule over men, who are not willing that God should rule over them.