Then the Lord said to Moses, "Go to Pharaoh. For I have hardened his heart and the hearts of his courtiers, in order that I may display these My signs among them, and that you may recount in the hearing of your sons and of your sons' sons how I made a mockery of the Egyptians and how I displayed My signs among them--in order that you may know that I am the Lord."
So Moses and Aaron went to Pharaoh and said to him, "Thus says the Lord, the God of the Hebrews, 'How long will you refuse to humble yourself before Me? Let My people go that they may worship Me. For if you refuse to let My people go, tomorrow I will bring locusts on your territory. They shall cover the surface of the land, so that no one will be able to see the land. They shall devour the surviving remnant that was left to you after the hail; and they shall eat away all your trees that grow in the field. Moreover, they shall fill your palaces and the houses of all your courtiers and of all the Egyptians--something that neither your fathers nor fathers' fathers have seen from the day they appeared on earth to this day.'" With that he turned and left Pharaoh's presence.
Pharaoh's courtiers said to him, "How long shall this one be a snare to us? Let the men go to worship the Lord their God! Are you not yet aware that Egypt is lost?" So Moses and Aaron were brought back to Pharaoh and he said to them, "Go, worship the Lord your God! Who are the ones to go?" Moses replied, "We will all go, young and old: we will go with our sons and daughters, our flocks and herds; for we must observe the Lord's festival." But he said to them, "The Lord be with you the same as I mean to let your children go with you! Clearly, you are bent on mischief. No! You menfolk go and worship the Lord, since that is what you want." And they were expelled from Pharaoh's presence.