There is a commandment to obliterate Amalek. Shaul Hamelech was commanded to obliterate Amalek and failed. Dovid continued in the process, but obviously didn't destroy them completely. None of the ...
Similar to this question. How did Dovid Hamelech kill the Amaleikim when they were almost completely obliterated (their only survivor was a baby fathered by Agag on his last day) by Shaul Hamelech ...