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

Hereby ye shall be proued: by the life of Pharaoh, ye shall not goe hence, except your yongest brother come hither.

Send one of you which may fet your brother, and ye shall be kept in prison, that your words may be proued, whether there bee trueth in you: or els by the life of Pharaoh ye are but spies.