1 Samuel 15:1-3

1And Samuel said unto Saul, Jehovah sent me to anoint thee to be king over his people, over Israel: now therefore hearken thou unto the voice of the words of Jehovah. 2Thus saith Jehovah of hosts, I have marked that which Amalek did to Israel, how he set himself against him in the way, when he came up out of Egypt. 3Now go and smite Amalek, and utterly destroy all that they have, and spare them not; but slay both man and woman, infant and suckling, ox and sheep, camel and ass.