Genesis 41:27-31

The seven thin and ugly cows that came up after them are seven years; and also the seven thin ears, dried up and scorched by the east wind, they are seven years of famine and hunger. This is the message just as I have told Pharaoh: God has shown Pharaoh what He is about to do. Listen very carefully: seven years of great abundance will come throughout all the land of Egypt; but afterward seven years of famine and hunger will come, and [there will be such desperate need that] all the great abundance [of the previous years] will be forgotten in the land of Egypt [as if it never happened], and famine and destitution will ravage and destroy the land. So the great abundance will become forgotten in the land because of that subsequent famine, for it will be very severe.