And the LORD did that thing on the morrow, and all the cattle of Egypt died: but of the cattle of the children of Israel died not one.

Wesley's Notes

9:6 All the cattle died - All that were in the field. The creature is made subject to vanity by the sin of man, being liable, according to its capacity, both to serve his wickedness, and to share in his punishment. The Egyptians worshipped their cattle; it was among them that the Israelites learned to make a god of a calf; in that therefore this plague meets with them. But not one of the cattle of the Israelites died - Doth God take care for oxen? Yes, he doth, his providence extends itself to the meanest of his creatures.

Jamieson-Fausset-Brown Bible Commentary

6. all the cattle of Egypt died-not absolutely every beast, for we find (Ex 9:19, 21) that there were still some left; but a great many died of each herd-the mortality was frequent and widespread. The adaptation of this judgment consisted in Egyptians venerating the more useful animals such as the ox, the cow, and the ram; in all parts of the country temples were reared and divine honors paid to these domesticated beasts, and thus while the pestilence caused a great loss in money, it also struck a heavy blow at their superstition.

Matthew Henry's Concise Commentary

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.