'Swear to Me' in the Bible

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.'

And David said to him, Canst thou bring me down to this troop? And he said, Swear to me by God, that thou wilt neither put me to death nor deliver me up into the hand of my master, and I will bring thee down to this troop.