Genesis 42:6-10

And Joseph was the governor over the land, and he it was that sold to all the people of the land: and Joseph’s brethren came, and bowed down themselves before him with their faces to the earth.

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

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.