2 Samuel 21:5-7

Then they replied, “It was Saul who planned to destroy us, to keep us from having any place at all in the territory of Israel. So let seven of Saul’s sons be handed over to us, and we will execute them before the LORD at Gibeon, on the mountain of the LORD.” “All right,” the king said, “I will do it.” The king spared Jonathan’s son Mephibosheth, who was Saul’s grandson, because of the oath David and Jonathan had sworn before the LORD.