Deuteronomy 18:9 - Reject foreign idolatrous practices.

Prohibition Against Adopting Gentile Practices

The verse (Devarim 18:9) warns Bnei Yisrael against learning the abominable practices of the nations inhabiting Eretz Canaan. Rashi explains that this refers specifically to idolatrous customs and immoral behaviors that were prevalent among those nations. The Torah emphasizes that upon entering the land, Israel must maintain spiritual purity and distinctiveness.

Rambam's Interpretation in Mishneh Torah

Rambam (Hilchot Avodat Kochavim 11:1) elaborates that this prohibition includes any practice associated with idolatry, even if performed without idolatrous intent. He lists examples such as astrology, divination, and sorcery—practices the Canaanites believed could influence the divine. The Rambam stresses that Jews must distance themselves entirely from these behaviors to avoid spiritual contamination.

Chizkuni's Insight on "Learning"

Chizkuni notes the phrasing "לֹא־תִלְמַד לַעֲשׂוֹת" ("you shall not learn to do") rather than a simple prohibition against doing. This implies that even the study of these practices is forbidden, as it could lead to their eventual performance. The Sifrei similarly teaches that one who studies idolatrous customs violates this prohibition, even without acting upon them.

Midrashic Perspective on Spiritual Boundaries

The Midrash Tanchuma (Re'eh 7) compares this commandment to a physician warning a patient to avoid contaminated food. Just as physical health requires vigilance, spiritual health demands separation from corrupting influences. The nations' "abominations" represent not only idolatry but also ethical decay, such as the cruelty and licentiousness for which Canaan was known (Vayikra 18:27).

Practical Implications in Halacha

• Darkei Emori: The Gemara (Sanhedrin 52b) extends this prohibition to superstitious customs of gentiles ("Darkei Emori"), even if unrelated to idolatry, if they lack rational basis.
• Modern Applications: Poskim like the Mishnah Berurah (YD 178:1) apply this principle to avoid imitating non-Jewish religious rituals or adopting secular practices that contradict Torah values.