Exodus 11:9
And the LORD said unto Moses, Pharaoh shall not hearken unto you; that my wonders may be multiplied in the land of Egypt. And the LORD said unto Moses, Pharaoh shall not hearken unto you; that my wonders may be multiplied in the land of Egypt.
It was foretold that Pharaoh would not heed Moses, in order that divine wonders might be multiplied in the land of Egypt. That refusal opened the way for wonder upon wonder, building toward the final plague. That last judgment revealed Jehovah as the God who executes judgment in the earth. At the same time those wonders laid bare the helplessness of Egypt's idols and established Jehovah's supremacy above them.