1 Samuel 20:14

“Only remember me when it goes well with you, and please show me lovingkindness by remembering me to Pharaoh and getting me out of this house.

Then Jonathan cut a covenant with David because he loved him as his own soul.

“As for the agreement of which you and I have spoken, behold, Yahweh is between you and me forever.”

So the two of them cut a covenant before Yahweh; and David stayed at Horesh while Jonathan went to his house.

“So now swear to me by Yahweh that you will not cut off my seed after me and that you will not destroy my name from my father’s household.”

Then David said, “Is there yet anyone left of the house of Saul, that I may show him lovingkindness for Jonathan’s sake?”

And the king said, “Is there not yet anyone of the house of Saul to whom I may show the lovingkindness of God?” And Ziba said to the king, “There is still a son of Jonathan who is crippled in both feet.”

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