Salvation and peace do not always erase the heavy memory of the past. In fact, times of ultimate comfort can actually deepen a person's awareness of past failures. As the Israelites finally receive God's absolute goodness and return to a healed, restored state, their natural emotional response will not simply be joy, but a profound and overwhelming sense of shame for their previous actions.
The primary approach among commentators notes that this intense shame is triggered specifically by the receipt of divine kindness. When God grants the nation grace instead of the harsh punishment they actually deserve, allowing them to live in total security without any fear, the memory of their past betrayal becomes unbearable. They will feel such deep disgrace that they will be unable to even lift their faces [רש״י, מצודת דוד]. As is human nature, a person who receives immense kindness from someone they previously wronged feels an infinitely greater sense of embarrassment when looking back on their own misdeeds [מצודת דוד]. From the safety of this promised peace, the people will finally be able to look back at their history with true recognition and regret [ביאור שטיינזלץ].
Commentators debate how the nation will process this heavy emotional realization. One perspective suggests that the people will actively carry this shame like a physical burden, suffering under the weight of their remorse [מצודת ציון, רד״ק]. A contrasting view understands this process not as a burden to be carried, but as an experience of total forgiveness, pardon, and even a divine forgetting of those very sins [רש י בשם מנחם, מלבי״ם].
Beyond the internal guilt over their sins, the people will also carry the memory of the intense humiliation and disgrace they endured at the hands of foreign nations during their exile, which served as a direct punishment for their rebellion [רד״ק, מלבי״ם]. Ultimately, this lingering memory of their past sins and the humiliation of exile will stand in sharp contrast to their new reality. They will live safely on their land, resting in the complete confidence that they will never be exiled again [מלבי״ם].