1 Samuel 20:12-17

Then Jonathan said to David, “The LORD, the God of Israel, be witness! When I have sounded out my father about this time tomorrow, or the third day, behold, if there is good feeling toward David, shall I not then send to you and make it known to you? If it please my father to do you harm, may the LORD do so to Jonathan and more also, if I do not make it known to you and send you away, that you may go in safety. And may the LORD be with you as He has been with my father. If I am still alive, will you not show me the lovingkindness of the LORD, that I may not die? You shall not cut off your lovingkindness from my house forever, not even when the LORD cuts off every one of the enemies of David from the face of the earth.” So Jonathan made a covenant with the house of David, saying, “May the LORD require it at the hands of David’s enemies.” Jonathan made David vow again because of his love for him, because he loved him as he loved his own life.