A vivid poetic image captures the profound joy of the upcoming redemption, where even the physical devastation of the city is invited to participate in the celebration. The very ruins of Jerusalem, its destroyed and empty houses, are called upon to open their mouths and raise their voices in joyful song [מצודת דוד, צאינה וראינה]. The primary approach among commentators is that this represents a sudden burst of pure, musical joy, though it can also be understood as an invitation to speak with absolute clarity [אבן עזרא]. Poetically, these shattered structures do not sing alone; their voices merge seamlessly with the calls of the watchmen and messengers who have already announced the good news [מלבי״ם].
This invitation to the ruins raises a deeper question about the desolate walls of Jerusalem. If the future city is destined to exist without physical borders, what comfort is there for the old walls? Their ultimate comfort lies in a transformed purpose. The walls will be rebuilt not for defense, but for a purely spiritual mission: to separate the holy from the mundane and to keep impurity outside the city limits [אהבת יהונתן].
The root of this overwhelming joy is that God has finally comforted His people, ending their suffering and replacing it with goodness. This comfort is deeply tied to the gathering of the exiles. Jerusalem itself feels this consolation as its empty spaces are once again filled with its returning children [מלבי״ם]. Beyond the return of the people, this comfort involves a dramatic physical transformation of the land to ensure its absolute purity. In His mercy, God will reshape the earth, lowering mountains and raising valleys to completely erase any lingering trace of places where idol worship once took place [נחל שורק, חומת אנך].
Ultimately, this culminates in the complete redemption of Jerusalem. The city will be entirely freed from the foreign nations that once ruled over it [מצודת דוד], paving the way for the restoration and rebuilding of the fallen tabernacle of David [נחל שורק].