Bible Verses About Oaths: Custom of swearing by the life of the king

By this you shall be tested. By the life of Pharaoh, you shall not go out from here, unless your youngest brother comes here.

Send one of you, and let him get your brother, and you shall be bound, that your words may be tested, whether there is truth in you, or else by the life of Pharaoh surely you are spies.”