Genesis 42:33-34

And the man, the lord of the country, said to us, ‘By this [test] I will know that you are honest men: leave one of your brothers here with me and take grain for your starving households and go. Bring your youngest brother to me; then I will know that you are not spies, but that you are honest men. Then I will return your [imprisoned] brother [back] to you, and you may trade and do business in the land.’ ”