Why were the Israelites in Goshen safe from the death of the firstborn?
They were safe from the death of the firstborn because the blood was applied to their door as an act of faith, not because of their goodness or anything they had earned. Scripture gives no indication any Jews were lost; every Jewish household in Goshen evidently had the blood on the door.
Les explains that the Israelites in Goshen had nothing to worry about or fear; they were absolutely secure, not because they had earned it or were good, but solely because of the blood on the door. That was an act of faith. If they had scoffed and refused to put the blood on the door, they would not have been safe and would have lost their firstborn. But Scripture gives no indication any Jews were lost; evidently every Jewish household in Goshen had the blood applied and was safe. Les compares this to being under the blood in the New Testament—safe and secure—while qualifying that this does not give license. He notes they were sinners just like we are, yet the blood applied made them totally safe and secure. He also says the exodus from Egypt was God's redemption of the nation, and he plans to go into Romans and Ephesians.