Genesis 42:17

14 And Joseph saith unto them, `This [is] that which I have spoken unto you, saying, Ye [are] spies,

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.

18 And Joseph saith unto them on the third day, `This do and live; God I fear!

19 if ye [are] right men, let one of your brethren be bound in the house of your ward, and ye, go, carry in corn [for] the famine of your houses,

20 and your young brother ye bring unto me, and your words are established, and ye die not;` and they do so.