Jamieson, Fausset and Brown on 1 Samuel 15:13-23

13-23. Saul said unto him, Blessed be thou of the Lord: I have performed the commandment of the Lord--Saul was either blinded by a partial and delusive self-love, or he was, in his declaration to Samuel, acting the part of a bold and artful hypocrite. He professed to have fulfilled the divine command, and that the blame of any defects in the execution lay with the people. Samuel saw the real state of the case, and in discharge of the commission he had received before setting out, proceeded to denounce his conduct as characterized by pride, rebellion, and obstinate disobedience. When Saul persisted in declaring that he had obeyed, alleging that the animals, whose bleating was heard, had been reserved for a liberal sacrifice of thanksgiving to God, his shuffling, prevaricating answer called forth a stern rebuke from the prophet. It well deserved it--for the destination of the spoil to the altar was a flimsy pretext--a gross deception, an attempt to conceal the selfishness of the original motive under the cloak of religious zeal and gratitude.