Deuteronômio 12:30 Halacá: Mishneh Torah, Foreign Worship and Customs, Kitzur Shulchan Arukh, Sefer HaMitzvot & Sefer HaChinukh

The idolaters compiled many books of worship, defining its principle manner of service, its works and its laws; but the Holy One, blessed be He! charged us not to read those books at all, not to think of idolatry generally nor of aught of its details. Moreover, to look at it is forbidden, as it is said: "Turn ye not unto idols" (Lev. 19.4.); and of thinking on this subject it is said: "And that thou inquire not after their gods, saying, How did these nations serve their god"? (Ibid.), which is a warning that thou shalt not inquire concerning its manner of practice, though thou art not worshiping it, for this very inquiry causes a turning after it and to imitate their practice, as it is further said: "Even so will I do likewise" (Ibid.).²Shabbat, 149a; Sifra, Lev. 19; Sanhedrin, 100b. C. G.

We are not permitted to follow the ways of the gentiles, nor adopt their styles in dress or in hair style or similar things, as it is said: "You shall not follow the ways of the gentile."³Leviticus 20:23. It is [also] said: "In their ways you shall not follow"⁴Leviticus 18:3. It is [also] said: "Guard yourself lest you be ensnared to follow them."⁵Deuteronomy 12:30. You should not wear a garment which is specifically worn by them as a symbol of ostentation, such as a garment of high-ranking officers. For example, the Talmud states:⁶Maseches Sanhedrin 74a. that it is forbidden for a Jew to be similar to them even in regard to shoelaces; if their practice was to tie one way and the practice of Jews to tie another way, or if their practice was to wear red shoelaces and Jews wear black shoelaces because the color black indicates humility, submissiveness and modesty. [In all such instances] it is forbidden for a Jew to deviate. From these examples everyone should learn how to apply these standards to his time and place. A garment designed for showiness or immodesty must not be worn by a Jew, but rather his clothing should be made in a style which suggests humility and modesty. The following is mentioned in Sifrei: You should not say that since they go out with scarlet I shall go out with scarlet, since they go out with kulsin (the word kulsin meaning weaponry) I also shall go out with kulsin, because these practices are indicative of arrogance and haughtiness which are not the heritage of Jacob. Rather, our heritage demands of us to be modest and humble, and not be influenced by the haughty. Similarly, any custom or statute of which there is a suspicion of idolatrous intent or background should be avoided by Jews. Similarly, you should not cut your hair or style your hair as they do, but rather you should be distinct, in your clothing and speech and all other endeavors just as you are distinct in your perspectives and concepts. Similarly, it is said: "I have set you apart from the nations."⁷Leviticus 20:26.

The idolaters fixed many kinds of service for each and every image and form, and the service of one is unlike the service of the other; for example, Peor, whose mode of worship it is for one to have himself exposed before it, or Mercury, which is worshiped by having stones thrown at it or from it, and many more like services were inaugurated to images. Therefore, if one reverses the service by exposing himself to Mercury or by throwing stones at Peor, he is not guilty, for he must worship it after the manner of its service, as it is said: "How used these nations to serve their gods? even so will I do likewise" (Deut. 12.30). The subject being such, and because thereof, a tribunal, judging cases of idolatry should know the modes of its worship, seeing that no punishment of stoning is pronounced on idolaters unless they know that the mode of worship is identical with the testimony presented at the trial.²Ibid. C.