"When the LORD goes through the land to strike down the Egyptians, he will see the blood on the top and sides of the door frame and will pass over that doorway, and he will not permit the destroyer to enter your houses and strike you down."
If God is all knowing, why would God need the Israelites to smear blood on their doorways, if God knew who was who?
If there is only one God, who was the destroyer?
How can God order the murder of the first born, if God is all good?
If God is all mighty, why would a destroyer be necessary?