Matthew Henry Commentary Exodus 8:20-32

"And Jehovah said unto Moses, Rise up early in the morning, and stand before Pharaoh; lo, he cometh forth to the water; and say unto him, Thus saith Jehovah, Let my people go, that they may serve me. Else, if thou wilt not let my people go, behold, I will send swarms of flies upon thee, and upon they servants, and upon thy people, and into thy houses: and the houses of the Egyptians shall be full of swarms of flies, and also the ground whereon they are. And I will set apart in that day the land of Goshen, in which my people dwell, that no swarms of flies shall be there; to the end thou mayest know that I am Jehovah in the midst of the earth. And I will put a division between my people and thy people: by to-morrow shall this sign be. And Jehovah did so; and there came grievous swarms of flies into the house of Pharaoh, and into his servants` houses: and in all the land of Egypt the land was corrupted by reason of the swarms of flies. And Pharaoh called for Moses and for Aaron, and said, Go ye, sacrifice to your God in the land. And Moses said, It is not meet so to do; for we shall sacrifice the abomination of the Egyptians to Jehovah our God: lo, shall we sacrifice the abomination of the Egyptians before their eyes, and will they not stone us? We will go three days` journey into the wilderness, and sacrifice to Jehovah our God, as he shall command us. And Pharaoh said, I will let you go, that ye may sacrifice to Jehovah your God in the wilderness; only ye shall not go very far away: entreat for me. And Moses said, Behold, I go out from thee, and I will entreat Jehovah that the swarms of flies may depart from Pharaoh, from his servants, and from his people, to-morrow: only let not Pharaoh deal deceitfully any more in not letting the people go to sacrifice to Jehovah. And Moses went out from Pharaoh, and entreated Jehovah. And Jehovah did according to the word of Moses; and he removed the swarms of flies from Pharaoh, from his servants, and from his people; there remained not one. And Pharaoh hardened his heart this time also, and he did not let the people go." — Exodus 8:20-32 (ASV)

Pharaoh was early at his false devotions to the river; and should we seek more sleep and more slumber when any service to the Lord is to be done? The Egyptians and the Hebrews were to be distinguished in the plague of flies. The Lord knows those who are his, and will make it apparent, perhaps in this world, certainly in the next, that he has set them apart for himself. Pharaoh unwillingly entered into a treaty with Moses and Aaron.

He is content that they should sacrifice to their God, provided they do it in the land of Egypt. But it would be an abomination to God if they offered the Egyptian sacrifices; and it would be an abomination to the Egyptians if they offered to God the objects of the Egyptians' worship, namely, their calves or oxen. Those who would offer acceptable sacrifice to God must separate themselves from the wicked and profane. They must also withdraw from the world.

Israel cannot keep the feast of the Lord, either among the brick-kilns or among the flesh-pots of Egypt. And they must sacrifice as God commands, not otherwise. Though they were in slavery to Pharaoh, yet they must obey God's commands. Pharaoh consents for them to go into the wilderness, provided they do not go so far that he could not bring them back again. Thus, some sinners, in a pang of conviction, part with their sins, yet are reluctant for them to go very far away; for when the fear is over, they will return to them again.

Moses promised the removal of this plague. But Pharaoh must not deal deceitfully any more. Be not deceived; God is not mocked: if we think we can cheat God by a sham repentance and a false surrender of ourselves to him, we will inflict a fatal deceit upon our own souls. Pharaoh returned to his hardness. Reigning lusts break through the strongest bonds, and make men presume and break their word.

Many seem earnest, but there is some reserve, some beloved, secret sin. They are unwilling to see themselves as in danger of everlasting misery. They will refrain from other sins; they do much, give much, and even punish themselves much. They will stop it sometimes and, as it were, let their sin depart a short distance; but will not make up their minds to part with all and follow Christ, bearing the cross.

Rather than that, they venture all. They are sorrowful, but they depart from Christ, determined to keep the world for now, and they hope for some future time when salvation may be obtained without such costly sacrifices; but, in the end, the poor sinner is driven away in his wickedness, and left without hope to lament his folly.