27. The plague of locust:

Hashem commands Moshe to approach Pharaoh: Hashem commanded Moshe to approach Pharaoh, as He has made his heart, and the heart of his servants, stubborn, in order to publicize His miracles amongst them.  “In order for the Jewish people to tell over to their children about the plagues that occurred in Egypt, and the miracles that I performed, and so you will know that I am G-d.”

Moshe warns Pharaoh of the upcoming plague: Moshe and Aaron approached Pharaoh and related to him “So said G-d, the G-d of the Jewish people: Until when will you refuse to answer my requests? Let my people go free so they can serve me. If you continue refusing to send my people, tomorrow I will bring locust into your country.” The locust will cover the earth until the point that the earth will not be seen. They will eat all the leftover produce that remained after the plague of hail. They will fill your homes and the homes of all Egyptians, as you have never seen before. Moshe and Aaron then left Pharaoh’s presence.

Pharaoh initially agrees to send out the Jewish people and then retracts: The servants of Pharaoh said to him “Until when will this matter be a source of suffering for us. Send the people so they can serve Hashem, as do you not know that Egypt is in ruins?” Pharaoh summoned Moshe and Aaron to return and said to them “Go serve your G-d. Who will be going?” Moshe replied, “We will leave with our lads, and elders, our sons and daughters, our sheep and cattle, as it is a festival for G-d.” Pharaoh replied to them “Let G-d be with you if I were to send you and your children, as I see evil coming towards you. This is not how it should be. The men shall go and serve Hashem, as that is your request.” Pharaoh then had Moshe and Aaron banished from his presence.

The locust come attack Egypt: Hashem told Moshe to stretch his hand over the land of Egypt and He will bring a storm of locust over the land. They will consume all the vegetation of the land that was left over from the plague of hail. Moshe did as he was instructed, and Hashem brought an eastern wind over Egypt which blew throughout that day and night. In the morning, the eastern wind carried the locust into Egypt and they swarmed the entire country like Egypt has never seen before and will never see again. They covered the land and the sky to the point that they darkened the land [preventing sunlight from passing]. They ate all the vegetation of the earth and all the fruits of the trees, to the point that no fruit or vegetation was left in the entire land of Egypt.

Pharaoh shows remorse: Pharaoh hurried to call Moshe and Aaron and told them that he has sinned against Hashem their G-d and against them. “Please forgive me for my sins one more time, and pray for me to your G-d, so that He should remove this death.”

Moshe prays, and Hashem ends the plague: Moshe left Pharaoh’s presence and prayed to Hashem. Hashem sent a very strong western wind that carried the locust swarm and dumped them into the river. Not one locust remained in Egypt.

Pharaoh refuses to let them go: Hashem hardened the heart of Pharaoh and he refused to let the people go.