Exodus 7:4-7

4But Pharaoh will still refuse to listen to you. Then I will show my authority and I will punish the Egyptians. I will bring my people, the Israelites, out of Egypt like an army.

5Then the Egyptians will know that I am the Lord. I will show my great strength in Egypt and I will lead the Israelites out from there.’

6Moses and Aaron obeyed all the commands of the Lord.

7Moses was 80 years old and Aaron was 83 years old when they spoke to Pharaoh.