1 Samuel 20:16

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

And Jonathan said to David, “Go in peace, inasmuch as we have sworn to each other in the name of Yahweh, saying, ‘Yahweh will be between me and you, and between my seed and your seed forever.’” Then he rose and departed, while Jonathan went into the city.

“For all of you have conspired against me so that there is no one who reveals in my ear when my son cuts a covenant with the son of Jesse, and there is none of you who is sorry for me or reveals in my ear that my son has caused my servant to rise up against me to lie in ambush, as it is this day.”

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?”

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.

Then Gedaliah the son of Ahikam, the son of Shaphan, swore to them and to their men, saying, “Do not be afraid of serving the Chaldeans; stay in the land and serve the king of Babylon, that it may go well with you.