What does Exodus 9:18 mean?
This is the fifth time a plague is said to either begin or end "tomorrow" (Exodus 8:10, 23, 29; 9:5). The eighth plague of locusts would also happen "tomorrow" (Exodus 10:4). After the exodus, the Lord would use "tomorrow" to schedule other activities related to the Israelites (Exodus 16:23; 17:9; 19:10; 32:5; Numbers 11:18). Because Pharaoh still refuses to release the Hebrew people (Exodus 9:17), God is sending another disaster.What's predicted is a vicious hailstorm. Pharaoh and other Egyptians would have understood the concept of hail: hard pieces of ice falling instead of raindrops. While exceedingly rare, even desert climates can experience hailstorms. Hailstones larger than a few centimeters, or about an inch, become extremely dangerous. When hailstones reach fist-sized chunks or larger, they can kill instantly. What's coming will be stronger than anything ever seen in the history of Egypt. This will be crippling, lethal hail (Exodus 9:19).
The destructive nature of hailstorms is a common element in Scripture. It appears in a battle involving Joshua (Joshua 10:11). Hail is part of God's creative power as discussed in Job (Job 38:22). In the end times (Revelation 8:7; 11:19), hailstones the size of people will fall (Revelation 16:21). Even in desert climates, hailstorms can wreak havoc.