Genesis 42:9-12, 14-17, 19-20

Joseph remembered the dreams he had dreamed about them, and said to them, “You are spies; you have come [with a malicious purpose] to observe the undefended parts of our land.” But they said to him, “No, my lord, for your servants have [only] come to buy food. We are all the sons of one man; we are honest men, your servants are not spies.” Yet he said to them, “No, you have come to see the undefended parts of our land.”

Joseph said to them, “It is as I said to you, you are spies. In this way you shall be tested: by the life of Pharaoh, you shall not leave this place unless your youngest brother comes here! Send one of you [back home], and let him bring your brother [here], while [the rest of] you remain confined, so that your words may be tested, [to see] whether there is any truth in you [and your story]; or else, by the life of Pharaoh, certainly you are spies.” Then Joseph put them all in prison for three days.

if you are honest men, let one of your brothers be confined in your [place here in] prison; but as for the rest of you, go, carry grain for the famine in your households, but bring your youngest brother to me, so your words will be verified and you will not die.” And they did so.