1 Samuel 24:20 KJV

18And thou hast shewed this day how that thou hast dealt well with me: forasmuch as when the LORD had delivered me into thine hand, thou killedst me not.

19For if a man find his enemy, will he let him go well away? wherefore the LORD reward thee good for that thou hast done unto me this day.

20And now, behold, I know well that thou shalt surely be king, and that the kingdom of Israel shall be established in thine hand.

21Swear now therefore unto me by the LORD, that thou wilt not cut off my seed after me, and that thou wilt not destroy my name out of my father’s house.

22And David sware unto Saul. And Saul went home; but David and his men gat them up unto the hold.