John Calvin Commentary Jeremiah 31:23

"Thus saith Jehovah of hosts, the God of Israel, Yet again shall they use this speech in the land of Judah and in the cities thereof, when I shall bring again their captivity: Jehovah bless thee, O habitation of righteousness, O mountain of holiness." — Jeremiah 31:23 (ASV)

He confirms in other words what he has said before; nor is the repetition, as we have said elsewhere, superfluous. It was difficult to convince the Jews that what they had already regarded as impossible could be accomplished, for by their perverseness they had, as it were, closed the door against the word of God. Since despair had thus gripped them and firmly bound their minds, it was necessary to speak at length on the subject, so that they might finally embrace the promise of deliverance. This is the reason why the Prophet used many words on the same subject.

Now he makes this preface: that he had his message from God; and he speaks in His name, so that this incredible thing might be believed by both the Israelites and the Jews. They shall yet, he says, say in the land of Judah and in its cities, when I shall restore their captivity. By these words, the Prophet brings the Israelites and the Jews, as it were, to the forefront, so that they might see placed before their eyes what they considered impossible. When I shall restore, therefore, their captivity, they shall again say, Bless thee may God, O dwelling-place of justice, O mountain of holiness.

It was not without reason that the Prophet used this manner of speaking, for Jerusalem, we know, was entirely overthrown, and the Temple torn down and even burned with fire. Since this was an awful and dreadful spectacle to all, a wonderful transformation is described here: that Zion would again be the mountain of holiness, and Jerusalem the habitation of justice, even though it was then a solitude and desolation.

This passage deserves special attention, so that we may know that God restores His Church as though He drew it up even from hell itself. Therefore, when no form of a Church is apparent, let us acknowledge that the power of God can raise it up. From where? Even, as has been said, from hell.