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

by this ye are proved: Pharaoh liveth! if ye go out from this--except by your young brother coming hither;

send one of you, and let him bring your brother, and ye, remain ye bound, and let your words be proved, whether truth be with you: and if not--Pharaoh liveth! surely ye are spies;'