1 Samuel 24:20-22

Young's Literal Translation

²⁰ `And, now, lo, I have known that thou dost certainly reign, and the kingdom of Israel hath stood in thy hand;

²¹ and, now, swear to me by Jehovah -- thou dost not cut off my seed after me, nor dost thou destroy my name from the house of my father.'

²² And David sweareth to Saul, and Saul goeth unto his house, and David and his men have gone up unto the fortress.