דברים, פרק ז׳, פסוק ד׳

The prohibition against intermarriage and assimilation stems from an existential spiritual threat to future generations rather than mere national differences. Maintaining a complete separation from surrounding nations is essential, as merging with a foreign family inevitably leads to an abandonment of faith, carrying a destructive impact on the nation's future. While the initial instruction addressed the seven Canaanite nations, the underlying spiritual danger extends this ban to all nations; wherever there is a risk of being drawn away from following God, the prohibition remains firmly in place [הכתב והקבלה, מלבי״ם, תורה תמימה].

Commentators explore the specific dynamics of how this spiritual seduction occurs, focusing on who acts as the inciter and who is led astray. One perspective suggests the warning applies to a Jewish man marrying a foreign woman. In this scenario, the foreign father-in-law and his family, who do not observe the commandments, are the ones who will influence and draw the Jewish son toward idol worship [שד״ל, חזקוני, בכור שור, העמק דבר בשם רבנו תם]. However, the primary approach among commentators is that the warning focuses on a Jewish daughter marrying a foreign man. Here, the foreign husband is the one who will mislead and tempt [נתינה לגר, חזקוני] the grandson—the child born to the Jewish daughter—distancing him from the path of the Torah [רש״י, אבן עזרא, רבנו בחיי, מזרחי].

This focus on the foreign husband misleading the grandson reveals a fundamental principle regarding Jewish identity. The use of a masculine, rather than feminine, phrasing for the act of turning the child away highlights a specific concern for the offspring of a Jewish daughter and a foreign man. Because lineage follows the mother, this grandson is considered fully Jewish. God is deeply concerned for the spiritual fate of this child. Conversely, a child born to a Jewish man and a foreign woman takes on the status of his mother and is not considered part of the congregation of Israel. Therefore, the same level of concern is not expressed regarding the foreign mother leading the child away from God, as the child is already outside the fold [רש״י, רבנו בחיי, תורה תמימה, בכור שור, אם למקרא].

The consequence of abandoning God is His immediate anger [ביאור שטיינזלץ] and severe punishment. This retribution arrives quickly because the warning was issued on the brink of war and heightened danger, a period when strict justice is applied without delay [העמק דבר]. Furthermore, the shifting perspectives between singular and plural within the text reflect the broader chaos and confusion generated by intermarriage. The spiritual fallout does not isolate itself to a single individual; rather, it ripples outward, disrupting the lives of the grandfather, the grandson, and the entire extended family [ברכת אשר על התורה].