Exodus 9:4-7

And the LORD will make a difference between the livestock of Israel and the livestock of Egypt. So nothing shall die of all that belongs to the children of Israel.” ’ ” Then the LORD appointed a set time, saying, “Tomorrow the LORD will do this thing in the land.” So the LORD did this thing on the next day, and all the livestock of Egypt died; but of the livestock of the children of Israel, not one died. Then Pharaoh sent, and indeed, not even one of the livestock of the Israelites was dead. But the heart of Pharaoh became hard, and he did not let the people go.