איוב, פרק ל״א, פסוק י״א

Complete separation from adultery requires guarding not just one's actions, but one's mind. The strict avoidance of even a passing thought or spoken word of immorality stems from two main concerns: the deep moral stain of the desire itself, and the severe legal consequences it brings [אלשיך].

The first concern highlights the inherent ugliness and disgrace of such behavior [רלב״ג]. At its core, this involves entertaining wicked thoughts of immorality [מצודת דוד, מצודת ציון]. Harboring such desires reveals a deep negative trait within a person's soul, showing a mind that sinks and roots itself in forbidden ideas [מלבי״ם]. Therefore, the mere existence of the thought is a profound moral failure, even before any physical action takes place.

Beyond the moral decay, this behavior constitutes a severe crime that demands heavy punishment [מלבי״ם באור המילות, ביאור שטיינזלץ]. It is an offense fundamentally tied to the concepts of strict law and justice [מצודת ציון]. Commentators offer different perspectives on how this justice is carried out. On one hand, the sheer severity of the offense means the sinner deserves to face judgment and endure suffering as a direct consequence [רש״י, אבן עזרא]. On the other hand, this is not a matter left solely to God's heavenly judgment. Instead, it falls squarely under the jurisdiction of the human legal system [אלשיך]. Earthly judges are tasked with delivering a harsh and decisive verdict against the offender. Often, this legal process is initiated by the demands of the wronged husband [מלבי״ם], and the resulting sentence from the court can be as severe as the death penalty.