Genesis 42:15

12 and he saith unto them, `No, but the nakedness of the land ye have come to see;`

13 and they say, `Thy servants [are] twelve brethren; we [are] sons of one man in the land of Canaan, and lo, the young one [is] with our father to-day, and the one is not.`

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!