"As soon as I leave you," Moses said, "I will pray to the LORD, so that tomorrow the swarms of flies will depart from Pharaoh and his officials and his people. But Pharaoh must not act deceitfully again by refusing to let the people go and sacrifice to the LORD."

Exodus 8:8
Pharaoh summoned Moses and Aaron and said, "Pray to the LORD to take the frogs away from me and my people. Then I will let your people go, that they may sacrifice to the LORD."

Exodus 8:15
When Pharaoh saw that there was relief, however, he hardened his heart and would not listen to Moses and Aaron, just as the LORD had said.

Exodus 9:30
But as for you and your officials, I know that you still do not fear the LORD our God."

Jeremiah 42:4
"I have heard you," replied Jeremiah the prophet. "I will surely pray to the LORD your God as you request, and I will tell you everything that the LORD answers; I will not withhold a word from you."

And Moses said, Behold, I go out from you, and I will entreat the LORD that the swarms of flies may depart from Pharaoh, from his servants, and from his people, to morrow: but let not Pharaoh deal deceitfully any more in not letting the people go to sacrifice to the LORD.