Exodus 9:27-35

Then Pharaoh summoned Moses and Aaron. “This time I have sinned,” he said to them. “The LORD is in the right, and I and my people are in the wrong. Pray to the LORD, for we have had enough thunder and hail. I will let you go; you don’t have to stay any longer.” Moses replied, “When I have gone out of the city, I will spread out my hands in prayer to the LORD. The thunder will stop and there will be no more hail, so you may know that the earth is the LORD’s. But I know that you and your officials still do not fear the LORD God.” (The flax and barley were destroyed, since the barley had headed and the flax was in bloom. The wheat and spelt, however, were not destroyed, because they ripen later.) Then Moses left Pharaoh and went out of the city. He spread out his hands toward the LORD; the thunder and hail stopped, and the rain no longer poured down on the land. When Pharaoh saw that the rain and hail and thunder had stopped, he sinned again: He and his officials hardened their hearts. So Pharaoh’s heart was hard and he would not let the Israelites go, just as the LORD had said through Moses.