When the battle intensified against Saul, the archers overtook him and wounded him critically.
The day of recompence has now come, in which Saul must account for the blood of the Amalekites which he had sinfully spared, and that of the priests which he had more sinfully spilt; that of David too, which he would have spilt, must come into the account. Now his day has come to fall, as David foresaw, when he should descend into battle and perish, Sa1 26:10.
Commenting on 1 Samuel 31:1-7
And the battle went sore against Saul,.... Pressed heavy upon him; he was the butt of the Philistines, they aimed at his person and life: and the archers hit him; or "found him" (a); the place where was, and directed their arrows at him: and he was sore wounded of the archers; or rather "he was afraid" of them, as the Targum, for as yet...
the battle went sore against Saul, &c.--He seems to have bravely maintained his ground for some time longer; but exhausted with fatigue and loss of blood, and dreading that if he fell alive into the enemy's hands, they would insolently maltreat him (Jos 8:29; Jos 10:24; Jdg 8:21), he requested his armor bearer to despatch him. However, that officer refused to do so.