The dark mountains are referred to as Babylon and the entire land of the Chaldeans, as noted in the beginning of Isaiah’s vision against Babylon, where it states, "Upon the dark mountain you shall lift up a standard." Therefore, it is commanded that until they are led into captivity to face the tribulations of enslavement, they ought to repent. While they long for the light, they may find themselves sitting in darkness. The prophet warns that if you refuse to heed His call, then in that hidden place or, as interpreted by Aquila, in darkness, your soul will weep. According to the Septuagint, this sorrow arises from the presence of pride, leaving you unable to even groan, for fear of offending the eyes of the victors.
The Savior instructs, “Work while it is day; the night comes when no one can work.” Isaiah also prophesies of this time, when "the stars of heaven, and Orion, along with all the heavenly bodies shall cease to give their light; the sun shall be darkened, and the moon shall not shine." Likewise, Zephaniah confirms this, declaring, "A day of trouble and distress, a day of devastation and desolation, a day of darkness and gloom, a day of cloud and thick darkness."
Thus, prior to the arrival of judgment and the stumbling of our feet on these dark mountains, which symbolize the opposing forces set for torment, let us repent. In our waiting for the light, may we not be engulfed by the night’s darkness. If we neglect this duty, the soul, whether of the Lord or the prophet, shall weep on account of our pride for not attending to God's words. Therefore, the prophet exclaims, “Jerusalem shall mourn,” capturing the depth of grief felt, because the Lord’s flock has been taken captive.
Let us address the Jews, and to all who cling merely to a simplistic and destructive narrative, warning that if they are inattentive to the mysteries concealed in darkness, as spoken of in the psalm, and fail to comprehend the parables and profound truths, then the prophet's soul, as well as their own, will lament in the face of pride due to their resistance against God. Consequently, there shall be unending weeping and eternal grief, for the flock of the Lord is led away into captivity by the true Nebuchadnezzar.