1 Samuel 31:4-8

Then Saul said to his armor bearer, “Draw your sword and pierce me through with it, otherwise these uncircumcised Philistines will come and pierce me through, and abuse me.” But his armor bearer was unwilling, because he was very fearful. So Saul took his sword and fell on it.

When his armor bearer saw that Saul was dead, he also fell on his sword and died with him.

So Saul died with his three sons, his armor bearer, and all his men on that day together.

Now when the people of Israel who were on the other side of the valley, with those who were beyond the Jordan, saw that the men of Israel had fled and that Saul and his sons were dead, they abandoned the cities and fled; then the Philistines came and settled in them.

It came about on the next day, when the Philistines came to strip those killed, that they found Saul and his three sons fallen on Mount Gilboa.