Genesis 42:16-20

Send one of you and have him get your brother, while you remain confined, so that your words may be tested, whether there is truth in you. But if not, by the life of Pharaoh, you are certainly spies!”

So he put them all together in prison for three days.

Now Joseph said to them on the third day, “Do this and live, for I fear God:

if you are honest men, let one of your brothers be confined in your prison; but as for the rest of you, go, carry grain for the famine of your households,

and bring your youngest brother to me, so that your words may be verified, and you will not die.” And they did so.