Was it God himself who killed the Egyptian’s firstborns?
Exodus 11:4 Moses then said: “This is what Jehovah has said, ‘About midnight I am going out into the midst of Egypt, 5 and every firstborn in the land of Egypt will die…
Exodus 12:1 Jehovah now said to Moses and Aaron in the land of Egypt:...12 For I will pass through the land of Egypt on this night and strike every firstborn in the land of Egypt, from man to beast; and I will execute judgment on all the gods of Egypt. I am Jehovah.
Exodus 12:23 (NOG, Names of God Bible) Yahweh will go throughout Egypt to kill the Egyptians. When he sees the blood on the top and sides of the doorframe, Yahweh will pass over that doorway, and he will not let the destroyer come into your home to kill you.
Hebrews 11:28 By faith he observed the Passover and the splashing of the blood, so that the destroyer might not harm their firstborn.
Exodus 9:23 So Moses stretched out his rod toward the heavens, and Jehovah sent thunder and hail, and fire fell down to the earth, and Jehovah kept making it rain down hail on the land of Egypt.
What kind of fire did God use here? Next scripture seems to have the answer:
Psalms 78:48 He gave their beasts of burden over to the hail and their livestock to the lightning bolts. 49 He inflicted his burning anger on them, fury and indignation and distress, companies of angels bringing calamity.
Why do we need to know about the Exodus? Well it helps to understand the Revelation book.
Revelation 19:18 And there were flashes of lightning and voices and thunders, and there was a great earthquake unlike any that had occurred since men came to be on the earth, so extensive and so great was the earthquake….21 Then great hailstones, each about the weight of a talent, fell from heaven on the people, and the people blasphemed God because of the plague of hail, for the plague was unusually great.