Because thou obeyedst not the voice of Jehovah, and didst not execute his fierce wrath upon Amalek, therefore hath Jehovah done this thing unto thee this day.

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.

επειδη δεν υπηκουσας εις την φωνην του Κυριου, ουδε εξετελεσας τον μεγαν θυμον αυτου κατα του Αμαληκ, δια τουτο ο Κυριος εκαμεν εις σε το πραγμα τουτο την ημεραν ταυτην·

Because thou obeyedst not the voice of the Lord, nor executedst his fierce wrath upon Amalek, therefore hath the Lord done this thing unto thee this day.