What is the criterion for imitating the disbelievers? Specifically, regarding the clothing we now see that is shared between Muslims and disbelievers, such as the jacket and the trousers?

The questioner : I mentioned the saying of the Messenger of Allah (peace and blessings be upon him), to the effect of: ; so what is the criterion for imitating the disbelievers? Especially now, we find that some garments are worn by both the disbeliever and the Muslim, such as these trousers in work settings, and also, does imitation include the shoe or the boot? We import them from abroad. Do woolen garments for the cold, like the jacket, fall under this?

The Shaykh : The answer, as explained by the Shaykh al-Islam Ibn Taymiyyah (may Allah have mercy on him) in his noble book "Iqtida' al-Sirat al-Mustaqim Mukhalafat Ahl al-Jahim" (Following the Straight Path by Opposing the People of the Hellfire), is that imitation has degrees; the lowest is disliked (makruh) in the sense of being discouraged, and the highest is forbidden (haram). Indeed, if prohibition is accompanied by considering it permissible, it leads its practitioner to disbelief and the path of misguidance. The stronger the appearance of imitation is in a person, the higher the degree of opposition and disobedience. I will give some examples to clarify this issue due to its precision. For example, the jacket; as he said,The questioner : it is worn by both the Muslim and the non-Muslim, so no type of imitation of the disbeliever appears in this garment. It can be said to be a universal garment, worn by all nations; it is not the emblem of one nation over another. Since that is the case, in this example we say: there is no harm in wearing the jacket and the like, because the cause, which is imitating the disbelievers, is absent. Accordingly, the scholars understood the hadith of al-Mughirah ibn Shu'bah (may Allah be pleased with him), the summary of which is that they were on a journey, so they stopped at a place. When morning came, the Prophet (peace and blessings be upon him) went out to relieve himself, and al-Mughirah ibn Shu'bah was with him. When he wanted to perform ablution (wudu') and al-Mughirah poured water on him, he tried to uncover his arms; but he could not, because he was wearing a Roman tunic—so goes the hadith—he was wearing a Roman tunic with tight sleeves. When he could not roll up the sleeves, he took off the tunic, threw it over his shoulders, and washed his arms. The scholars said: the fact that this tunic was Roman was not a barrier to wearing it; because it was the clothing of the Arabs and the non-Arabs alike, without distinction between them.
However, if the garment is still the emblem of the nation of disbelief; then the detailed discussion mentioned earlier applies, and its ruling varies according to the phenomenon of imitation. I am now giving two contrasting examples to illustrate the sin of imitation. This man who wears the jacket over a shirt, for example, or over the sarwal and the like—and by sarwal I do not mean the trousers that are part of the traditional Muslim clothing, which do not reveal the private parts and do not cling to them—this, as we said earlier, has no appearance of imitation. But if he wears the jacket over the trousers, there is no doubt that the appearance of imitation has now emerged where it was not present before. It was not present with just the jacket, but when he wore the trousers, this phenomenon appeared. Especially since it can be said that the trousers are not part of the Muslim clothing; because they cling to the private parts, and the Muslim garment must be loose and wide, not clinging to the private parts, especially when he stands before Allah to pray.
And we see—regrettably—today in this mosque or others, the man wearing trousers—if this expression is correct—bowing and prostrating; we see his thighs are defined, and the worshippers behind him see it. Indeed, sometimes, with great regret, what is seen by the person behind this worshipper is the major private part between the thighs. How can this be the clothing of Muslims? Rather, it is the clothing of the disbelievers who do not forbid what Allah and His Messenger have forbidden. So whoever wears the trousers, there is no doubt that he is imitating the disbelievers.
But now, the second and final example: this man wearing trousers, if he increases the imitation by wearing a cap or a beret on his head, he has placed the covering of disbelief on his head. There is no imitation greater than this; so this is undoubtedly forbidden (haram), and the wearing of trousers before this is forbidden to a lesser degree. There are other degrees, and we should summarize the speech on them with one hadith that has no relation to imitation; because the types of imitation are many and very many, and I summarized the statement on them earlier. The closer the phenomenon of imitation is to prohibition, and the lower this phenomenon descends until it disappears and vanishes, then it enters the circle of the permissible (mubah).