8 Then the Lord said to Moses and Aaron, "Take handfuls of soot from a brick kiln, and have Moses toss it into the air while Pharaoh watches. 9 The ashes will spread like fine dust over the whole land of Egypt, causing festering boils to break out on people and animals throughout the land." 10 So they took soot from a brick kiln and went and stood before Pharaoh. As Pharaoh watched, Moses threw the soot into the air, and boils broke out on people and animals alike. 11 Even the magicians were unable to stand before Moses, because the boils had broken out on them and all the Egyptians.
Matthew Henry's Commentary on Exodus 9:8-11
Commentary on Exodus 9:8-12
(Read Exodus 9:8-12)
When the Egyptians were not wrought upon by the death of their cattle, God sent a plague that seized their own bodies. If lesser judgments do not work, God will send greater. Sometimes God shows men their sin in their punishment. They had oppressed Israel in the furnaces, and now the ashes of the furnace are made a terror to them. The plague itself was very grievous. The magicians themselves were struck with these boils. Their power was restrained before; but they continued to withstand Moses, and to confirm Pharaoh in his unbelief, till they were forced to give way. Pharaoh continued obstinate. He had hardened his own heart, and now God justly gave him up to his own heart's lusts, permitting Satan to blind and harden him. If men shut their eyes against the light, it is just with God to close their eyes. This is the sorest judgment a man can be under out of hell.