To-morrow the Lord shall do this - By thus foretelling the evil, he showed his prescience and power; and from this both the Egyptians and Hebrews must see that the mortality that ensued was no casualty, but the effect of a predetermined purpose in the Divine justice.

And the Lord appointed a set time,.... For the coming of this plague, that it might plainly appear it came from him, and was not owing to any natural cause:

saying, tomorrow the Lord shall do this thing in the land; thus giving him time and space, as he had often done before, to consider the matter well, repent of his obstinacy, and dismiss the people of Israel, and so prevent the plague coming upon the cattle, as threatened.

And the LORD appointed a set time, saying, To morrow the LORD shall do this thing in the land.

9:1-7 God will have Israel released, Pharaoh opposes it, and the trial is, whose word shall stand. The hand of the Lord at once is upon the cattle, many of which, some of all kinds, die by a sort of murrain. This was greatly to the loss of the owners; they had made Israel poor, and now God would make them poor. The hand of God is to be seen, even in the sickness and death of cattle; for a sparrow falls not to the ground without our Father. None of the Israelites' cattle should die; the Lord shall sever. The cattle died. The Egyptians worshipped their cattle. What we make an idol of, it is just with God to remove from us. This proud tyrant and cruel oppressor deserved to be made an example by the just Judge of the universe. None who are punished according to what they deserve, can have any just cause to complain. Hardness of heart denotes that state of mind upon which neither threatenings nor promise, neither judgements nor mercies, make any abiding impression. The conscience being stupified, and the heart filled with pride and presumption, they persist in unbelief and disobedience. This state of mind is also called the stony heart. Very different is the heart of flesh, the broken and contrite heart. Sinners have none to blame but themselves, for that pride and ungodliness which abuse the bounty and patience of God. For, however the Lord hardens the hearts of men, it is always as a punishment of former sins.