"And I came to Jerusalem and was there three days," etc. He wanders through various parts of the destroyed city, carefully scrutinizing each, and considers anxiously how they ought to be repaired. Thus it is with spiritual teachers, often rising at night and by diligent investigation examining the condition of the holy Church while others are resting; so that they may vigilantly inquire how those things which are defiled or ruined by the wars of vices may be corrected and raised by castigating. But the wall of Jerusalem is laid waste, and the conduct of the faithful is soiled by earthly and low affections; the gates are consumed by fire, when even those who ought to open the way of life to others through teaching, abandoning the office of truth, become equally torpid with common inertia, and serve temporal cares.
Source: Commentary on Ezra and Nehemiah