Genesis 42:7-20

7And Joseph saw his brethren, and he knew them, but made himself strange unto them, and spake roughly with them; and he said unto them, Whence come ye? And they said, From the land of Canaan to buy food. 8And Joseph knew his brethren, but they knew not him. 9And Joseph remembered the dreams which he dreamed of them, and said unto them, Ye are spies; to see the nakedness of the land ye are come. 10And they said unto him, Nay, my lord, but to buy food are thy servants come. 11We are all one man’s sons; we are true men, thy servants are no spies. 12And he said unto them, Nay, but to see the nakedness of the land ye are come. 13And they said, We thy servants are twelve brethren, the sons of one man in the land of Canaan; and, behold, the youngest is this day with our father, and one is not. 14And Joseph said unto them, That is it that I spake unto you, saying, Ye are spies: 15hereby ye shall be proved: by the life of Pharaoh ye shall not go forth hence, except your youngest brother come hither. 16Send one of you, and let him fetch your brother, and ye shall be bound, that your words may be proved, whether there be truth in you: or else by the life of Pharaoh surely ye are spies. 17And he put them all together into ward three days.

18And Joseph said unto them the third day, This do, and live; for I fear God: 19if ye be true men, let one of your brethren be bound in your prison-house; but go ye, carry grain for the famine of your houses: 20and bring your youngest brother unto me; so shall your words be verified, and ye shall not die. And they did so.