1 Samuel 24:15-21
English Standard Version
16As soon as David had finished speaking these words to Saul, Saul said, "Is this your voice, my son David?" And Saul lifted up his voice and wept.
17He said to David, "You are more righteous than I, for you have repaid me good, whereas I have repaid you evil.
18And you have declared this day how you have dealt well with me, in that you did not kill me when the Lord put me into your hands.
19For if a man finds his enemy, will he let him go away safe? So may the Lord reward you with good for what you have done to me this day.
20And now, behold, I know that you shall surely be king, and that the kingdom of Israel shall be established in your hand.
21Swear to me therefore by the Lord that you will not cut off my offspring after me, and that you will not destroy my name out of my father 's house."