The process of redemption and the building of the Temple is fraught with seemingly insurmountable obstacles. Yet, these massive barriers are destined to crumble before the smooth, unstoppable progress of God's chosen leader, culminating in a moment of widespread joy.
A great mountain serves as a powerful symbol for these looming threats. The primary approach among commentators views this mountain as a historical and political obstacle. It represents the regional ministers [רש"י] or adversaries like Sanballat and his associates [רד"ק, צאינה וראינה] who actively tried to halt the construction of the Second Temple. Though they appear as an impassable peak, they will lose their authority and be flattened into a smooth, even plain [מצודת ציון]. This leveling allows Zerubbabel to bypass them with ease and continue his holy work. However, there is a perspective that challenges this historical identification, arguing that Sanballat was merely an informer whose only real power lay in his words. Under this view, he does not warrant the grand title of a mountain, a metaphor typically reserved for a mighty and exalted king [אברבנאל].
Shifting from the historical to the future and spiritual realms, other commentators interpret the mountain differently. Some suggest it represents King Gog, who will mistakenly believe he has the strength to stand against the Messianic King, only to be swiftly removed from the path [מצודת דוד]. Others propose that the mountain is literally Mount Moriah. In this vision, the mountain itself will be commanded to flatten into a plain so that the original foundation stone, which had sunk deep into the earth over the centuries, can be extracted [מלבי"ם]. On a purely allegorical level, the mountain represents any obstacle [ביאור שטיינזלץ], and more specifically, the Evil Inclination. To the righteous, this inner struggle appears as a massive, intimidating peak, but it is ultimately destined to be uprooted and leveled [אהבת יהונתן, אדרת אליהו, צאינה וראינה].
Once the path is cleared, the chosen leader brings forth a primary, highly valued stone [מצודת ציון, ביאור שטיינזלץ]. Some explain this architecturally as the master plumbline or weight stone held by the builder to carefully guide the construction of a magnificent edifice [רש"י, אבן עזרא]. Others view it as a symbol of completion and closure: just as Zerubbabel laid the very first stone to initiate the building, he will be granted the privilege of seeing the work through to its absolute end [רד"ק, צאינה וראינה]. Looking to the future, it is the Messianic King who will bring forth this precious stone to establish the foundation of the ultimate Temple [מצודת דוד]. Returning to the allegorical interpretation, the extraction of the stone represents the final removal of the Evil Inclination, often referred to as a heart of stone. Only after this spiritual barrier is entirely eradicated can the complete ingathering of the exiles take place [אהבת יהונתן, אדרת אליהו].
The completion of this monumental task is met with the roaring, joyous uproar of a massive crowd [רש"י, מצודת ציון, אבן עזרא]. As the final stone is set in place, the people will erupt in loud cheers, declaring its extraordinary beauty and grace. The repetition of the word grace in their cheers serves to amplify their deep admiration and awe [מצודת דוד, רד"ק]. This stands in stark contrast to the building of the Second Temple, which failed to find favor in the eyes of the elders who wept as they remembered the glory of the First Temple. Instead, this future edifice will inspire perfect, unblemished joy, finding absolute favor in the eyes of everyone without exception [מלבי"ם].