What was the final and worst plague God sent on Egypt?
God's final and worst plague was the death of the firstborn. It struck every Egyptian house and even the livestock, hitting families and parents directly. Israel was spared only through the blood of the Passover lamb on the doorposts and remaining inside, so the death angel passed over them.
Les teaches that God had been pouring out the plagues upon the Egyptians, and while Israel experienced the first few, God later put a division so the Jews no longer experienced the plagues that fell on Egypt. The final one was the worst of all, and it struck home to families and parents: the death of the firstborn. The angel would fly over, and every house in Egypt would lose the firstborn; everything firstborn, even the livestock, would die. Israel had an out, but it depended on their faith: they had to put the blood of the Passover lamb on the doorposts and stay within the safety of their home, and the death angel would pass over. Les notes this is the beginning of what Jews still celebrate today in the Spring of the Year, Passover. He also makes the point that Passover and Atonement are two totally different Feast Days: Passover in the Spring, Atonement or Yom Kippur in the Fall. Christ is our Passover, and for now the focus is the Passover aspect, the protection given by the blood of the Lamb.