Exodus 9:27-35

And Pharaoh sent and called for Moses and Aaron, and said to them, “I have sinned this time. The LORD is righteous, and my people and I are wicked. Entreat the LORD, that there may be no more mighty thundering and hail, for it is enough. I will let you go, and you shall stay no longer.” So Moses said to him, “As soon as I have gone out of the city, I will spread out my hands to the LORD; the thunder will cease, and there will be no more hail, that you may know that the earth is the LORD’s. But as for you and your servants, I know that you will not yet fear the LORD God.” Now the flax and the barley were struck, for the barley was in the head and the flax was in bud. But the wheat and the spelt were not struck, for they are late crops. So Moses went out of the city from Pharaoh and spread out his hands to the LORD; then the thunder and the hail ceased, and the rain was not poured on the earth. And when Pharaoh saw that the rain, the hail, and the thunder had ceased, he sinned yet more; and he hardened his heart, he and his servants. So the heart of Pharaoh was hard; neither would he let the children of Israel go, as the LORD had spoken by Moses.