Genesis 42:8-13

And Joseph knew his brethren, but they knew not him. And 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. And they said unto him, Nay, my lord, but to buy food are thy servants come. We are all one man's sons; we are true men, thy servants are no spies. And he said unto them, Nay, but to see the nakedness of the land ye are come. And they said, 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.