Genesis 42:16-19

16Send one of you, that he may fetch your brother, but ye shall be imprisoned, and your words shall be put to the proof, whether the truth is in you; and if not, as Pharaoh lives, ye are spies.

17And he put them in custody three days.

18And Joseph said to them the third day, This do, that ye may live: I fear 1God.

19If ye are honest, let one of your brethren remain bound in the house of your prison, but go ye, carry grain for the hunger of your households;