Exodus 5 - 8

God sends Moses to Pharaoh, saying “let My people go”, but Pharaoh refuses.

God turns the Nile to blood, He brings up a plague of frogs upon the land, He turns the dust of the ground into a plague of gnats, and then brings vast swarms of flies against Pharaoh and the Egyptians.

But in the face of these plagues, Pharaoh’s heart remains hard, and he refuses to let them go.