Exodus 11:10 KJV
And Moses and Aaron did all these wonders before Pharaoh: and the Lord hardened Pharaoh’s heart, so that he would not let the children of Israel go out of his land.
Exodus 11:10, King James Version
In context
9 And the Lord said unto Moses, Pharaoh shall not hearken unto you; that my wonders may be multiplied in the land of Egypt.
10 And Moses and Aaron did all these wonders before Pharaoh: and the Lord hardened Pharaoh’s heart, so that he would not let the children of Israel go out of his land.