1 Samuel 15:13 - Ellicott's Commentary On The Whole Bible

Blessed be thou of the Lord. — Saul must have been fully conscious that he had failed to carry out the will and command of the Eternal King of Israel. In the late war, undertaken for the definite and solemn purpose of exterminating a wicked and bloodthirsty people, whose continued existence worked terrible evil upon the adjacent countries, he, disregarding the express instructions of the prophet of the Lord for his own covetous purposes, had not destroyed all, but reserved some of the living spoil for himself. Conscious of all this, he still dared to come forward, and to congratulate the prophet upon the fulfilment of the Lord’s command. But Saul’s words of self-gratulation were evidently feigned; in his heart he knew he had been faithless.