John Calvin Commentary Isaiah 27:10

"For the fortified city is solitary, a habitation deserted and forsaken, like the wilderness: there shall the calf feed, and there shall he lie down, and consume the branches thereof." — Isaiah 27:10 (ASV)

Yet the defenced city shall be desolate. Here the connective ו (vau) is generally thought to mean for, and some take it to mean otherwise. This leads to two possible interpretations. If we translate it as because, the Prophet would be assigning a reason for the previous statement; however, that interpretation is rejected by the context and is entirely absurd. It is more plausibly taken to mean otherwise, as this threat could be appropriately introduced: “If you do not repent, you see what awaits you; the defenced city shall be like a wilderness.” But I consider that interpretation a departure from the natural meaning, and therefore I prefer to understand it as signifying nevertheless or yet.

The Prophet means that Jerusalem and the other cities of Judea must nevertheless be destroyed, and that, although the Lord wishes to spare His people, it is impossible for them to be preserved. Godly people would have become disheartened when they saw that holy city overthrown and the temple demolished. But from these predictions they learned that God would have many ways to preserve the Church, and they were supported by that consolation. So then, the Prophet intended to address this very severe temptation. From this we also learn that we should never lose courage, even if we suffer every hardship and even if the Lord treats us with the utmost severity. Although this threat extends to the whole of Judea, I think it probable that it relates chiefly to Jerusalem, which was the capital of the nation.

There shall the calf feed. This metaphor is frequently used by the prophets when they speak of the desolation of any city, for they immediately add that it will become a place for pasture. Here we should take into account the judgment of God, which places calves and brute beasts in the place of the Jews who had profaned the land by their crimes. Having been adopted by God as His children, they certainly should have obeyed such a kind Father. But since they had shaken off the yoke and given themselves up to wickedness, it was the just reward for their ingratitude that the land would be possessed by better inhabitants—not from the human race, but from brute beasts.

And shall browse on its tops. What he says about the tops tends to show the desolation more strongly, as if he had said that there will be such an abundance of grass that the calves will eat only the tender parts. סעף (sāīph) also signifies branch; but since branches naturally grow high, I take it here to mean summit or top. It might also be thought that there is an allusion to the beauty of the city. As its houses were formerly lofty and magnificent, when these have been thrown down, nothing will be seen in it but herbs and leaves, the tops of which the calves, enjoying abundant pasture, will eat in disdain.