Exodus 9:1-9

1 Then the LORD said unto Moses, Go in unto Pharaoh and tell him, Thus saith the LORD God of the Hebrews, Let my people go that they may serve me.
2 For if thou refuse to let them go and wilt hold them still,
3 behold, the hand of the LORD is upon thy livestock which are in the field, upon the horses, upon the asses, upon the camels, upon the cows, and upon the sheep: there shall be a very grievous pestilence.
4 And the LORD shall separate between the livestock of Israel and the livestock of Egypt so that nothing shall die of all that is of the sons of Israel.
5 And the LORD appointed a set time, saying, Tomorrow the LORD shall do this thing in the land.
6 And the next day the LORD did that thing, and of all the livestock of Egypt many died, but of the livestock of the sons of Israel not one died.
7 Then Pharaoh sent, and, behold, there was not one of the livestock of the sons of Israel dead. But the heart of Pharaoh hardened, and he did not let the people go.
8 And the LORD said unto Moses and unto Aaron, Let each of you take handfuls of soot from the furnace, and let Moses sprinkle it toward heaven in the sight of Pharaoh.
9 And it shall become dust upon all the land of Egypt, which shall cause boils breaking forth with blisters upon man and upon beast, throughout all the land of Egypt.