The Lord of armies says, I will give punishment to Amalek for what he did to Israel, fighting against him on the way when Israel came out of Egypt.

Go now and put Amalek to the sword, putting to the curse all they have, without mercy: put to death every man and woman, every child and baby at the breast, every ox and sheep, camel and ass.

And Saul came to the town of Amalek, and took up his position in the valley secretly.

And Saul said, Truly, I have done the orders of the Lord and have gone the way the Lord sent me; I have taken Agag, the king of Amalek, and have given the Amalekites up to destruction.

Because you did not do what the Lord said, and did not give effect to his burning wrath against Amalek. So the Lord has done this thing to you today.