Exodus 10:13
And Moses stretched forth his rod over the land of Egypt, and the LORD brought an east wind upon the land all that day, and all that night; and when it was morning, the east wind brought the locusts. And Moses stretched forth his rod over the land of Egypt, and the LORD brought an east wind upon the land all that day, and all that night; and when it was morning, the east wind brought the locusts.
At God's command Moses stretched out his rod and his hand over Egypt, and the Lord brought an east wind upon the land all that day and all that night, so that when it was morning the east wind brought the locusts. The plague came after warning and a choice, for Moses and Aaron told Pharaoh that if he would not humble himself and let Israel go, God would bring locusts into the coasts of Egypt to cover the face of the earth and eat the residue that had escaped the hail. It happened exactly as they said after he refused to let Israel go.
The locusts went up over all the land of Egypt and rested in all its coasts, very grievous with none like them before or after. They covered the face of the whole earth so that the land and the sky were darkened, and ate every herb of the land and all the fruit of the trees the hail had left, so that no green thing remained in trees or herbs of the field through all Egypt, and they nearly destroyed Egypt. The Egyptians were afraid that after eating everything in the field the locusts would attack and devour the people. God had suffered Pharaoh to resist and had borne with his continual rebellion so that He might show His great signs and wonders before Pharaoh and before Israel. The locusts were meant to confirm Israel's faith in Him as the only true and living God, to give unmistakable evidence of the difference He placed between the Egyptians and His people, to supply what they should tell in the ears of their sons and their sons' sons about what He wrought in Egypt and His signs among them so they would know He is the Lord, and to cause all nations to know that although Israel had been bound down by hard labor and despised He had chosen them as His peculiar people and would work for their deliverance in a wonderful manner.
The plague was directed against the worship of Serapis, whom the Egyptians trusted to protect their land from locusts, and it showed that Serapis was powerless and that Jehovah alone could protect them. It was a dreadful visitation of God's wrath and judgment, sent because Pharaoh chose to receive the plagues rather than submit to God, and without remorse he saw his whole kingdom under the miracle of these dreadful judgments. Pharaoh was very slow to yield to the God of heaven, yielding only a little under grievous affliction and taking back what he granted when the affliction was removed, persisting in rebellion even after Egypt was ruined.
Then Pharaoh hastily called Moses and Aaron, confessed sin against God and against them, asked forgiveness only this once, and begged entreaty that God would take away this death. Moses entreated the Lord, and the Lord turned a mighty strong west wind that took away the locusts and cast them into the Red Sea, leaving not one locust in all the coasts of Egypt. But the Lord hardened Pharaoh's heart so that after relief he hardened his heart and would not let Israel go despite his humility and promise while death threatened him. After this plague Pharaoh granted that the wives and children might go with the men but would not let the cattle go, and then Moses told him the angel of God would slay the firstborn.