Why were the Israelites not afraid of the death angel in Egypt?
The Israelites were not afraid of the death angel because the blood of the sacrificial lamb was applied to their doorposts and lintel. As people of faith, they were secure, knowing the blood covered them, so the death angel would pass over them and they had nothing to fear.
Les explains that these Jews had been slaves in Egypt and were told that if they killed the sacrificial lamb, placed the blood on the two doorposts and the lintel, and sat in their little huts, then at the stroke of midnight the death angel would go over Egypt and kill every firstborn male. As Israel huddled in their small abodes, they were not in fear of the death angel if they were people of faith, because the blood was on the door and they had absolutely nothing to fear. They did not stand quivering in their boots; they were secure, knowing the blood was on the door and they were covered. Les then brings this up to the church age, showing that even as our Passover, when Christ died on the Roman cross and His blood was shed, when we come under that blood, we are passed over from any judgment. The crucial point often left out, Les says, is the blood.
And the blood shall be to you for a token upon the houses where ye are: and when I see the blood, I will pass over you, and the plague shall not be upon you to destroy you, when I smite the land of Egypt.