משלי, פרק ו׳, פסוק ל״ב

Adultery is a deeply irrational act driven by an urge for self-destruction. A person who steals might do so out of a desperate need to survive, driven by hunger and physical distress. In contrast, a person who commits adultery acts without any genuine necessity. Because there is no survival instinct driving this choice, the behavior reveals a deep flaw in the person's mind and character. He is viewed as someone completely lacking sense and intellect [ביאור שטיינזלץ, עמנואל הרומי]. The primary approach among commentators is that this foolishness is defined by the absence of any survival need, which sharply separates the adulterer from the desperate thief [רש״י, מצודת דוד].

Furthermore, the act fails to even achieve its basic goal of satisfying a physical urge. Giving in to this desire does not bring true fulfillment; it only feeds the craving and makes it grow stronger [מלבי״ם]. Consequently, committing such an offense inflicts a fatal blow upon a person's soul [רש״י]. It is an act of extreme self-sabotage, chosen only by someone who actively wishes to ruin himself [מצודת דוד, ביאור שטיינזלץ, עמנואל הרומי].

A final, critical difference between stealing and adultery lies in the possibility of making amends. A thief can always return the stolen money and clear his conscience. However, an adulterer completely destroys his soul, which is a piece of God from above. The spiritual damage inflicted is so profound that the soul can never be fixed or created anew [אלשיך].