דברים, פרק כ״ז, פסוק כ״א

Engaging in relations with an animal is a severe betrayal of human nature, carrying a profound curse for its absolute deviation from the natural order. The primary approach among commentators is that this transgression is uniquely characterized by its secrecy. A person committing such an act hides it, and the animal, lacking a voice, cannot protest or cry out for help [אבן עזרא, ביאור שטיינזלץ]. Because of this hidden nature, the curse is grouped with other offenses committed privately within the home. These include striking a neighbor in secret or engaging in incest with female relatives—such as a sister, mother-in-law, or a father's wife—who are frequently present in the household. In these situations, a person might give in to base, animalistic lusts, carrying out the sin far from the public eye [רשב״ם, קיצור בעל הטורים].

Naturally, human beings find true intimacy and satisfaction only with their own kind. Consequently, crossing this natural boundary does not stem from ordinary human desire. Instead, it is driven by a deliberate intent to rebel and provoke God [שפתי כהן]. The scope of this prohibition is entirely comprehensive, encompassing every type of creature, whether a domesticated animal, a wild beast, or a bird [ברכת אשר על התורה]. Furthermore, no distinction is made regarding the gender of the animal. Unlike a human victim who might speak up or fight back, an animal cannot voice any opposition, rendering such details irrelevant [אבן עזרא].

Beyond the literal meaning, this curse is also understood allegorically to warn against highly inappropriate human unions [העמק דבר, מלבי״ם]. It serves as a metaphor for marrying someone from an unrefined, ignorant background. Such individuals lack moral guidance, basic manners, and spiritual knowledge, growing up wild and uncultivated. Because they do not observe the laws of family purity, their physical state is metaphorically compared to that of an animal [תורה תמימה על התורה]. Similarly, this concept is applied to nomads who live in isolated tents far from established communities. Their transient lifestyle separates them from essential communal structures like ritual baths. Consequently, women in these groups are forced to travel great distances for purification, leaving them vulnerable to immorality and the pursuit of wicked men [תורה תמימה על התורה].

This strict insistence on suitable marriages and the rejection of unfit unions is not merely a new standard introduced when the Torah was given. Rather, it is a foundational principle that was practiced long before. This deep-rooted value is evident in how carefully Abraham and Isaac selected wives, as well as in the tribes' firm refusal to allow Dinah to marry Shechem [מלבי״ם].