“Please pardon your maid’s boldness. For Hashem will grant my lord an enduring house, because my lord is fighting the battles of Hashem, and no wrong is ever to be found in you” I SAMUEL 25:28 (The Israel Bible™)
Metzudat David explains that the prophetess Avigail is warning David that he should kill only if necessary as part of Hashem’s wars against enemies such as the Philistines, but not in order to exact revenge. This is one of the foundations of Jewish military ethics: The people of Israel are required to fight wars only to defend themselves and to strengthen the Promised Land. The State of Israel follows this biblical mandate, as can be seen even in the name given to the Israeli army: The Israel Defense Forces, or in Hebrew, Tz’va HaHaganah L’Yisrael (צבא ההגנה לישראל).