Exodus 7:1-2

7:1 So the Lord said to Moses, “See, I have made you like God to Pharaoh, and your brother Aaron will be your prophet. 7:2 You are to speak everything I command you, and your brother Aaron is to tell Pharaoh that he must release the Israelites from his land.

Exodus 7:9-10

7:9 “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.” 7:10 When Moses and Aaron went to Pharaoh, they did so, just as the Lord had commanded them – Aaron threw down his staff before Pharaoh and his servants and it became a snake.

Exodus 7:19

7:19 Then the Lord said to Moses, “Tell Aaron, ‘Take your staff and stretch out your hand over Egypt’s waters – over their rivers, over their canals, over their ponds, and over all their reservoirs – so that it becomes blood.’ There will be blood everywhere in the land of Egypt, even in wooden and stone containers.”