1 Samuel 15:7-11

And Saul smote the Amalekites, from Havilah as thou goest to Shur, that is before Egypt. And he took Agag the king of the Amalekites alive, and utterly destroyed all the people with the edge of the sword. But Saul and the people spared Agag, and the best of the sheep, and of the oxen, and of the fatlings, and the lambs, and all that was good, and would not utterly destroy them: but everything that was vile and refuse, that they destroyed utterly. Then came the word of Jehovah unto Samuel, saying, It repenteth me that I have set up Saul to be king; for he is turned back from following me, and hath not performed my commandments. And Samuel was wroth; and he cried unto Jehovah all night.