Genesis 42:15-17

Young's Literal Translation

¹⁵ by this ye are proved: Pharaoh liveth! if ye go out from this -- except by your young brother coming hither;

¹⁶ 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;'

¹⁷ and he removeth them unto charge three days.