Exodus 7:4-9 New English Translation (NET)

4. Pharaoh will not listen to you. I will reach into Egypt and bring out my regiments, my people the Israelites, from the land of Egypt with great acts of judgment.

5. Then the Egyptians will know that I am the Lord, when I extend my hand over Egypt and bring the Israelites out from among them.

6. And Moses and Aaron did so; they did just as the Lord commanded them.

7. Now Moses was eighty years old and Aaron was eighty-three years old when they spoke to Pharaoh.

8. The Lord said to Moses and Aaron,

9. “When Pharaoh says to you, ‘Do a miracle,’ and you say to Aaron, ‘Take your staff and throw it down before Pharaoh,’ it will become a snake.”

Exodus 7