God tells Moses that he and Aaron will command Pharaoh to free the children of Israel, but that Pharaoh's heart will be hardened and he will not obey. God promises to send signs and wonders so that the Egyptians will know that He is the God.
Pharaoh asks Moses and Aaron for a miracle and, as God had commanded, Aaron throws down his staff and it becomes a snake. The sorcerers and magicians then duplicate this feat - they throw down their own staffs and they too become snakes, but Aaron's "snake" then eats the other snakes.
But Pharaoh's heart is hardened and he refuses to let Israel go. Moses then, at God's command, turns the waters of Egypt into blood, killing all of the fish and ruining the water supply, but Pharaoh is unrelenting.
WIKIPEDIA ARTICLES: Moses - Aaron - Pharaoh - God - Israelite - Plagues of Egypt
CHAPTER TEXT: King James - World English - American Standard