But the king spared Mephibosheth the son of Jonathan, the son of Saul, because of the sworn oath of Yahweh which [was] between them, between David and Jonathan the son of Saul.

Then David said, "[Is] there still anyone who [is] left for the house of Saul that I may show loyal love to him for the sake of Jonathan?" Now Saul's household had a servant whose name [was] Ziba, so they summoned him to David, and the king asked him, "[Are] you Ziba?" He said, "{At your service}!" Then the king said, "But [is] there still anyone of Saul's household that I may show the loyal love of God with him?" And Ziba said to the king, "There [is] still a son of Jonathan [who is] lame in the feet." read more.
The king said to him, "Where [is] he?" And Ziba said to the king, "{He [is] here} in the house of Makir the son of Ammiel in Lo Debar." So King David sent and brought him from the house of Makir the son of Ammiel from Lo Debar. So Mephibosheth the son of Jonathan, the son of Saul, came to David. And he fell on his face and did obeisance. David said, "Mephibosheth," and he said, "{I am ready to serve you}." Then David said to him, "Don't be afraid, for {I will certainly show} loyal love to you for the sake of Jonathan your father, and I will restore to you all the lands of Saul your father. And you shall always eat food at my table."