1 Chronicles 10:4-8

Then Saul said to his armor bearer, “Draw your sword and thrust me through with it, otherwise these uncircumcised Philistines will come and abuse me.” But his armor bearer would not, for he was very afraid. So Saul took his own sword and fell on it.

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

So Saul died with his three sons, and all those of his house died together.

When all the people of Israel who were in the valley saw that they had fled, and that Saul and his sons were dead, they abandoned their cities and fled; and the Philistines came and lived in them.

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