John Calvin Commentary Isaiah 26:5

"For he hath brought down them that dwell on high, the lofty city: he layeth it low, he layeth it low even to the ground; he bringeth it even to the dust." — Isaiah 26:5 (ASV)

For he will bring down the inhabitants of loftiness. He now explains more fully what that power of God is, about which he spoke. It is the power that we ourselves experience, and which is exercised for our benefit. The two clauses are therefore closely connected: that the proud are laid low by the power of God, and that the lowly and despised are put in their stead. For it would not have provided full comfort to tell us, in the first place, that the proud will be laid low, if he had not also added that the lowly will be exalted, so as to hold dominion over the proud. We therefore acknowledge that in our own experience God works powerfully for our salvation, and this gives us a reason for hope.

Under the word loftiness he includes not only bulwarks and fortifications of every kind (for the ancients were accustomed to build their cities in high places), but also wealth and magnificence. He therefore means that no defense can prevent God from casting down the wicked and laying them low. Towers and bulwarks, indeed, are not displeasing to God; but as it rarely happens that those who are strong and powerful are not proud, so loftiness frequently denotes pride. Undoubtedly, he speaks of the wicked, who have an abundance of arms, forces, and money, and imagine that they are protected against God Himself. He also comforts the Jews, as we have said before, because the invincible power of Babylon could have terrified them and thrown them into despair, if the Lord had not supported them by this promise: “You have no reason for being terrified at the greatness or strength of Babylon; for she will quickly fall, and will not stand before the power of the Lord.”