Moses and Exodus 22

The plague of boils began from a handful of soot which had been taken from the same kilns used by Pharaoh to make bricks, sometimes without straw, by the Hebrew slaves. God took the very thing Pharaoh used to cause pain for His people and used it to bring pain upon Pharaoh's people. These boils were so painful that the pagan priests could not practice their ceremonies, so during this plague only the Lord of the Israelites was being worshipped in all the land of Egypt.