Genesis 42:15-20

42:15 You will be tested in this way: As surely as Pharaoh lives, you will not depart from this place unless your youngest brother comes here. 42:16 One of you must go and get your brother, while the rest of you remain in prison. In this way your words may be tested to see if you are telling the truth. If not, then, as surely as Pharaoh lives, you are spies!” 42:17 He imprisoned them all for three days. 42:18 On the third day Joseph said to them, “Do as I say and you will live, for I fear God. 42:19 If you are honest men, leave one of your brothers confined here in prison while the rest of you go and take grain back for your hungry families. 42:20 But you must bring your youngest brother to me. Then your words will be verified and you will not die.” They did as he said.

Genesis 42:33-34

42:33 “Then the man, the lord of the land, said to us, ‘This is how I will find out if you are honest men. Leave one of your brothers with me, and take grain for your hungry households and go. 42:34 But bring your youngest brother back to me so I will know that you are honest men and not spies. Then I will give your brother back to you and you may move about freely in the land.’”

Genesis 44:23

44:23 But you said to your servants, ‘If your youngest brother does not come down with you, you will not see my face again.’