שמואל א, פרק ל״א, פסוק ב׳

The tide of war turns disastrous as enemy forces relentlessly hunt down the Israelite royal family. During the fierce campaign, the Philistines aggressively pursue King Saul and his sons, closing the gap until they are locked in tight, physical combat [מצודת ציון, רד״ק, ביאור שטיינזלץ]. This intense, close-quarters fighting is a direct result of the king's fierce resistance. Because Saul fights with immense bravery and strength, the Philistines are forced to exert a stubborn effort, physically clinging to him in order to finally overpower him in hand-to-hand combat [מלבי״ם].

The tragedy culminates in the deaths of three of Saul's sons: Jonathan, Abinadab, and Malchishua. These three fall in this specific battle because they are the ones who regularly accompany their father to war, fighting and ultimately dying right by his side [רד״ק].

The absence of Saul's remaining son, Ish-bosheth, among the casualties is explained in two ways. One approach suggests that he survives because he is not a warrior and simply stays home during the conflict [רד״ק]. Another perspective argues that he is indeed present on the battlefield, but manages to successfully escape the slaughter alongside Abner [חומת אנך].