1 Samuel 20:42

“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 David received from her hand what she had brought him and said to her, “Go up to your house in peace. See, I have listened to your voice and granted your request.”

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