1 Samuel 15:4

Samuel also said unto Saul, The LORD sent me to anoint thee to be king over his people, over Israel: now therefore hearken thou unto the voice of the words of the LORD.

Thus saith the LORD of hosts, I remember that which Amalek did to Israel, how he laid wait for him in the way, when he came up from Egypt.

Now 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.

And Saul came to a city of Amalek, and laid wait in the valley.