Exodus 14:4-5

4I will harden Pharaoh’s heart so that he will pursue them. Then I will receive glory by means of Pharaoh and all his army, and the Egyptians will know that I am the Lord.” So the Israelites did this.

5When the king of Egypt was told that the people had fled, Pharaoh and his officials changed their minds about the people and said, “What have we done? We have released Israel from serving us.”