1 Samuel 31:6-8

New International Version - UK

⁶ So Saul and his three sons and his armour-bearer and all his men died together that same day.

⁷ When the Israelites along the valley and those across the Jordan saw that the Israelite army had fled and that Saul and his sons had died, they abandoned their towns and fled. And the Philistines came and occupied them.

⁸ The next day, when the Philistines came to strip the dead, they found Saul and his three sons fallen on Mount Gilboa.