NET
18 Since you did not obey the Lord and did not carry out his fierce anger against the Amalekites, the Lord has done this thing to you today.
Darby
18 Because thou didst not hearken to the voice of Jehovah, and didst not execute his fierce anger upon Amalek, therefore has Jehovah done this thing to thee this day.
KJV
18 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.