The land wherein thou swimmest - Egypt; so called, because intersected with canals, and overflowed annually by the Nile.

I will also water with thy blood the land in which thou (e) swimmest, [even] to the mountains; and the rivers shall be full of thee.
(e) As the Nile overflows in Egypt, so will I make the blood of your host overflow it.

And I will also water with thy blood the land wherewith thou swimmest,.... Where he resided, over which he ruled; alluding to his being compared to a fish, a whale, or a crocodile; and which land abounded with all good things, and he with them; instead of being watered with the waters of the Nile, by which it became fruitful, it should now be flooded with the blood of his army:
even to the mountains; an hyperbolical expression, signifying the vast quantity of blood that should be shed; see the like in Revelation 14:20,
and the rivers shall be full of them; of the carcasses of his army, and of the blood of them; they should lie about everywhere, on mountains and valleys, on the land and in the rivers; and which should now be turned into blood, as the rivers of Egypt of old were; and which figure is used to express the destruction of the antichristian states; see Exodus 7:20.

land wherein thou swimmest--Egypt: the land watered by the Nile, the the source of its fertility, wherein thou swimmest (carrying on the image of the crocodile, that is, wherein thou dost exercise thy wanton power at will). Irony. The land shall still afford seas to swim in, but they shall be seas of blood. Alluding to the plague (Exodus 7:19; Revelation 8:8). HAVERNICK translates, "I will water the land with what flows from thee, even thy blood, reaching to the mountains": "with thy blood overflowing even to the mountains." Perhaps this is better.

Even to the mountains - Blood shall be poured forth, as if it were to rise to the very mountains. Full of thee - O thy blood, and of thy carcasses cast into them.