Genesis 42:15
15 By this you shall be tested: by the life of Pharaoh, you shall not go from this place dunless your youngest brother comes here.
Genesis 42:19–20
19 if you are honest men, let one of your brothers remain confined where you are in custody, and let the rest go and carry grain for the famine of your households, 20 and bring your youngest brother to me. So your words will be verified, and you shall not die.” And they did so.