Genesis 42:6-9

6And Joseph, he was the governor over the land — he it was that sold [the corn] to all the people of the land. And Joseph's brethren came and bowed down to him, the face to the earth.

7And Joseph saw his brethren, and knew them; but he made himself strange to them, and spoke roughly to them, and said to them, Whence come ye? And they said, From the land of Canaan, to buy food.

8And Joseph knew his brethren, but they did not know him.

9And Joseph remembered the dreams that he had dreamt of them; and he said to them, Ye are spies: to see the exposed places of the land ye are come.