Exodus 7:2-5

2You must say whatever I command you; then Aaron your brother must declare it to Pharaoh so that he will let the Israelites go from his land.

3But I will harden Pharaoh’s heart and multiply my signs and wonders in the land of Egypt.

4Pharaoh will not listen to you, but I will put my hand into Egypt and bring the military divisions of my people the Israelites out of the land of Egypt by great acts of judgment.

5The Egyptians will know that I am the Lord when I stretch out my hand against Egypt and bring out the Israelites from among them.”