Physical suffering and deep, painful wounds often serve as a harsh but necessary tool for cleansing a person of wrongdoing. The imagery used to describe this process is highly medical and physical, depicting the forceful scrubbing away of evil. This cleansing is compared to the vigorous polishing of weapons [מצודת ציון, אבן עזרא, ביאור שטיינזלץ], or alternatively, to the application of healing ointments and medical bandages [מלבי״ם, עמנואל הרומי]. The suffering takes the form of severe, bleeding injuries [אבן עזרא] or blows that are incredibly difficult to heal [מלבי״ם]. Alongside these visible injuries are hidden, internal strikes that penetrate deep into the body [עמנואל הרומי, אבן עזרא]. Sometimes, the pain of these deep wounds only surfaces long after the wrongdoing has occurred [ביאור שטיינזלץ], or they manifest as severe internal conditions, such as the accumulation of fluid in the body [רש״י].
The primary approach among commentators is that this suffering acts as a direct medicine for evil. Just as wisdom is considered the crowning glory of the elderly, these purifying wounds serve as the "glory" of the wicked, scrubbing away their sins and settling their spiritual debts [אבן עזרא, מצודת דוד, ביאור שטיינזלץ]. Because those who do wrong rarely change their ways through mere words of correction, physical blows become the only effective bandage and cure capable of removing their foolishness [עמנואל הרומי].
On a deeper psychological level, this process serves as a metaphor for repairing the mind and character. Healing a severe physical wound often requires painful, aggressive treatments, such as draining infection or removing diseased flesh. Similarly, a person with deeply corrupt habits or flawed thinking requires extreme intervention. To truly heal, they must force themselves to act in the complete opposite extreme of their negative trait, even if that extreme behavior seems harsh in itself, until they are entirely purified [רלב״ג]. Taking a different perspective, rather than viewing these wounds solely as a means of atonement, there is a direct cause and effect between sin and its consequence. When a person actively prepares and "polishes" themselves to commit a wrong, they inevitably bring these painful wounds and internal sicknesses upon themselves [רש״י].
Finally, this concept extends into practical guidance for the justice system. Criminals frequently attempt to hide their actions behind smooth talk and lies, using deception to cover up their evil just as cosmetics cover blemishes. Other times, their crimes are kept completely hidden from the public eye. Because of this, a judge or leader cannot rely on mercy alone. They are required to investigate fiercely and question aggressively to uncover the truth hiding behind a seemingly innocent surface [אלשיך].