John Gill Commentary Exodus 9

Then the Lord said unto Moses The same day the plague of the flies was removed: go in unto Pharaoh boldly, without any fear of him or his court: and tell him, thus saith the Lord God of the Hebrews : speak in the name of Jehovah, the God whom the Hebrews worship, and who owns them for his people, and has a special love for them, and takes a special care of them, and is not ashamed to be called their God, as poor and as oppressed as they be: let my people go , that they may serve me; this demand had been often made, and, though so reasonable, was refused.

For if you refuse to let them go
Continue to refuse, as he had done: and will hold them still ;
in the land, and under his dominion and oppression.

Behold, the hand of the Lord
Which was stronger than his, with which he held the Israelites: is upon your cattle which is in the field :
this takes in all in general, of which the particulars follow, though limited to such as were in the field, and so did not take in what were at home in their out houses and stables:

upon the horses :
of which there was great plenty in Egypt, as appears from various places of Scripture: upon the asses ;
used for carrying burdens from place to place: and upon the camels ;
used the like purposes, and to ride upon, and particularly to travel with through desert places for commerce, being able to proceed on without water for a considerable time: upon the oxen, and upon the sheep ;
oxen were for labour to plough with, and sheep for their wool, and all of them to trade with:

there shall be a very grievous murrain :
or "pestilence" ^F25 , a very noisome one, and which would carry off great numbers; the Targums of Onkelos and Jonathan render it a "death", as the Jews commonly call a pestilence, whether on man or beast, because it generally sweeps away large numbers.

FOOTNOTES:

• F25: (rbd) "pestis", V. L. Pagninus, Montanus, Piscator; "pestilentia", Drusius; so Tigurine version.

And the Lord shall sever between the cattle of Israel and the cattle of Egypt

Make such a difference and distinction between them, that the murrain should not be on the one, when it was on the other, and which was a very marvellous thing; and especially in the land of Goshen, where the Egyptians had much cattle, and Pharaoh himself, see (Genesis 47:6). And yet, though the cattle of Israel breathed in the same air, drank of the same water, and fed in the same pastures, they had not the murrain as the cattle of Egypt had; and the word here used signifies a marvellous separation, as has been observed on (Exodus 7:22).

and there shall nothing die of all that is the children's of Israel; not an horse, nor an ass, nor an ox, nor a sheep.

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.