So the king answered, "I will give them." The king exempted Mephibosheth, the son of Saul's son Jonathan, because of the promise to the LORD that existed between David and Saul's son Jonathan.

Later on, David asked, "Is there anyone left alive from Saul's household to whom I can show gracious love in memory of Jonathan?" A household servant of Saul named Ziba was called to appear before David, and the king asked him, "Are you Ziba?" "I am your servant," Ziba replied. At this the king asked, "Isn't there still someone left from Saul's household to whom I may show God's gracious love?" "There's Jonathan's son. He has maimed feet," Ziba answered. read more.
So David asked, "Where is he?" Ziba responded, "He's in Lo-debar at the home of Ammiel's son Makir." At this, King David sent for him and brought him from the home of Ammiel's son Makir in Lo-debar. When Mephibosheth, Jonathan's son and a grandson of Saul, approached David, he threw himself on his face out of respect. "Mephibosheth!" David said as he greeted him. "Hello! I am your servant," he replied. "Don't be afraid," David reassured him, "because I'm going to show gracious love to you in memory of your father Jonathan. I'm going to restore to you all the land that belonged to your grandfather Saul, and you'll always have a place at my table!"