Kapłańska 20:23 Halacha: Kitzur Shulchan Arukh, Mishneh Torah, Foreign Worship and Customs, Mishneh Torah, Negative Mitzvot & Sefer HaChinukh

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.

It is forbidden to follow the customs of the idolaters, or to imitate them neither in dress nor in hair-trimming and like customs, for it is said: "And ye shall not walk in the customs of the nation which I cast out before you" (Lev. 20.23), and it is also said: "And in their customs shall ye not walk" (Ibid. 18.3), and it is, moreover, said: Then take heed to thyself that thou be not snared by following them" (Deut. 12.30)—all of which pertain to one subject admonishing them not to be like unto them. Forsooth an Israelite shall be separated from them, and be recognized by his clothes and in his conduct as he is different than they are in education and tendencies. For even so it is said: "And have set you apart from the peoples, that ye should be Mine" (Lev. 20.26). An Israelite shall not wear a garment of a design particularly adopted by idolaters, nor raise hair-locks as their hair-locks; not shave the sides and leave the hair in the middle, such as is called a queue, nor shave the hair opposite his face, from ear to ear, and leave the locks at the back of his head as they do. He shall not build public places of the same design and architecture as are the palaces built for idolatry in order to attract a crowd as they do.²Sifra, Lev. 20; Abodah Zarah, 29a; Baba Kamma, 83a; Sotah, 49b; Tosefta, Shabbat Ch. 6. C. G.

Not to adopt the institutions of idolaters nor their customs, as it is said, “And ye shall not walk in the manners of the nation (which I am casting out before you) (Lev. 20:23).