Then the LORD said to Moses, "Stretch out your hand over the land of Egypt for the locusts, so that they may come upon the land of Egypt and eat every plant in the land, all that the hail has left." So Moses stretched out his staff over the land of Egypt, and the LORD brought an east wind upon the land all that day and all that night. When it was morning, the east wind had brought the locusts. The locusts came up over all the land of Egypt and settled on the whole country of Egypt, such a dense swarm of locusts as had never been before, nor ever will be again. They covered the face of the whole land, so that the land was darkened, and they ate all the plants in the land and all the fruit of the trees that the hail had left. Not a green thing remained, neither tree nor plant of the field, through all the land of Egypt. Then Pharaoh hastily called Moses and Aaron and said, "I have sinned against the LORD your God, and against you. Now therefore, forgive my sin, please, only this once, and plead with the LORD your God only to remove this death from me." So he went out from Pharaoh and pleaded with the LORD. And the LORD turned the wind into a very strong west wind, which lifted the locusts and drove them into the Red Sea. Not a single locust was left in all the country of Egypt. But the LORD hardened Pharaoh's heart, and he did not let the people of Israel go.
Exodus 10:12-20
With an almost monotonous similarity the process of devastation is again repeated, and the land is engulfed in another ruin more deadly and disastrous than before. And again Pharaoh is made to cry out in craven fear. But, as we believe, the point of no return has already been passed, and the depraved king's reaction is predictable: as soon as the plague is stayed, he will again change his mind about letting Israel go, and so it proves. It is impressive to see how 'spiritual' he sounds in 16, 17, and this should make us intent on piercing beyond religious jargon in our assessment of the professions men make. It is also interesting, however, to see that - even in the context of having in all probability sinned away his day of grace - God was still even then prepared to take him at his word, false though his heart was, and stay His hand. It is the extraordinary patience and long-suffering of God that stands out at every point, and this is one of the things that Paul stresses in Romans 9:22. It is not, of course, that the Lord only gradually discovered how deceitful and wily Pharaoh’s heart was, and was obliged in a moment of final discovery to deal with him in judgment. He knows the end from the beginning, but was prepared, in the strange interaction of divine sovereignty and human responsibility, to give him time and opportunity in which to repent. It is only when all doors are closed that mercy turns sadly and finally away from the human soul. What we read in the remainder of this chapter makes it clear that this point had now been reached, so far as Pharaoh was concerned.