In Exodus 8, God demonstrates to Pharaoh and Egypt that He has control over animals to use them for His agenda. He did multiple wonders.
Power over other powers
All power belongs to God. There is none powerful and supreme to overturn what He wants to do. Exodus 7 teaches us to trust Him and see His marvelous works.
God deals with our doubts
What do we do with our doubts when God's mission is at stake? In Exodus 6, we learn that Moses had complaints and doubts but God helped to revolve them and put His word on his mouth.

