Exodus 9:22
And the LORD said unto Moses, Stretch forth thine hand toward heaven, that there may be hail in all the land of Egypt, upon man, and upon beast, and upon every herb of the field, throughout the land of Egypt. And the LORD said unto Moses, Stretch forth thine hand toward heaven, that there may be hail in all the land of Egypt, upon man, and upon beast, and upon every herb of the field, throughout the land of Egypt.
The Lord commanded Moses to stretch his hand toward heaven so that hail would fall in all the land of Egypt, upon people and upon animals and upon every plant of the field. The command came after Pharaoh was warned to let Israel go, was told there is none like God in all the earth, was told of a coming grievous hail such as Egypt had never seen, and was told to gather servants and cattle from the field or they would die. The advance warning tested Egyptian pride and revealed whose hearts were affected.
Those who feared and believed the word of the Lord brought their servants and cattle into houses and barns and indoors, while those who did not regard and rejected it left them in the field. In this way God showed mercy in the midst of judgment by providing a way of escape for all who acted on the warning. When Moses obeyed and stretched his rod toward heaven, the storm came with thunder and hail and fire running along the ground and mingled with the hail, with lightning and thunder.
The time of each plague was announced beforehand, on the morrow, so it could not be dismissed as chance. The hail was unprecedented in Egypt and brought death and desolation where no lives had been taken before, smiting throughout Egypt all that was in the field, both man and beast, destroying every herb and breaking every tree. The flax and the barley were smitten because the barley was in ear and the flax was bolled, but the wheat and the rye were not smitten because they were not grown up. Only the land of Goshen where Israel lived had no hail and was spared.
The plague was an act of divine judgment that displayed God's power and demonstrated that the whole earth and its forces and elements are under the command of the God of the Hebrews and obey His voice. It humbled the proud Pharaoh who had asked who the Lord was that he should obey Him, so that he confessed that he had sinned and that he and his people were wicked and the Lord is righteous, and he asked Moses to intercede with God that the terrific thunder, lightning, and hail might cease. Moses spread his hands to stop the thunder and hail so Pharaoh would know the earth is the Lord's, yet Pharaoh refused to fear and would not let Israel go, showing that rebellion produces rebellion and continual opposition hardens the whole being against divine power. The only true safety of nations and individuals is obedience to the voice of God and standing on the side of truth and righteousness.