Halakhah zu Wajikra 20:26

FIFTH BOOK. I include in it precepts having reference to illicit sexual unions, and those that relate to forbidden foods; because, in these two regards, the Omnipresent sanctified us and separated us from the nations, and of both classes of precepts it is said, “And I have set you apart from the peoples” (Lev. 20:26), “.... who have set you apart from the peoples” (Lev. 20:24). I have called this book: The Book of Holiness.

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 20:33. 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.