1 Samuel 15:13

Blessed be thou of Jehovah. Saul meets Samuel with all external respect, and seems even to expect his approval, saying, I have performed the commandment of Jehovah. And so he had in the half way in which men generally keep God's commandments, doing that part which is agreeable to themselves, and leaving that part undone which gives them neither pleasure nor profit. Saul probably had thought very little about the exact terms of the command given him, and having successfully accomplished the main point of carrying out a vast foray against the Amalekites, regarded the captive king and the plundered cattle as proofs of his victory. The trophy at Carmel is a token of his own self satisfaction.