Genesis 42:33-34

Then the man, the lord of the land, said to us, ‘By this I shall know that you are honest men: leave one of your brothers with me, and take grain for the famine of your households, and go your way. Bring your youngest brother to me. Then I shall know that you are not spies but honest men, and I will deliver your brother to you, and you shall trade in the land.’”