Moses went out of the city from Pharaoh, and spread out his hands to the LORD; and the thunders and hail ceased, and the rain was not poured on the earth.
When Pharaoh saw that the rain and the hail and the thunders had ceased, he sinned yet more, and hardened his heart, he and his servants.
The heart of Pharaoh was hardened, and he didn’t let the children of Israel go, just as the LORD had spoken through Moses.