1 Samuel 20:12-17

20:12 Jonathan said to David, “The Lord God of Israel is my witness. I will feel out my father about this time the day after tomorrow. If he is favorably inclined toward David, will I not then send word to you and let you know? 20:13 But if my father intends to do you harm, may the Lord do all this and more to Jonathan, if I don’t let you know and send word to you so you can go safely on your way. May the Lord be with you, as he was with my father. 20:14 While I am still alive, extend to me the loyalty of the Lord, or else I will die! 20:15 Don’t ever cut off your loyalty to my family, not even when the Lord has cut off every one of David’s enemies from the face of the earth 20:16 and called David’s enemies to account.” So Jonathan made a covenant with the house of David. 20:17 Jonathan once again took an oath with David, because he loved him. In fact Jonathan loved him as much as he did his own life.