Employing something that yields benefit without harm—especially when it is not an act of worship or any of its adjuncts but belongs purely to worldly affairs—is permissible. You will notice that most of what Imām Aḥmad says on the matter bases the concession on a report from ʿUmar or on the action of Khālid ibn Maʿdān, so as to prove that the practice existed in the time of the early generations and that they approved it. In that case it counts as part of the Muslims’ own conduct, not the conduct of non-Arabs or of the People of the Book. This, then, is the force of the argument—not the mere fact that Khālid ibn Maʿdān once did it.

As for the evidence in this field from the other leading authorities among the Muslims—Companions, Followers, and the later jurists—it is far too abundant to cite even a tenth of it. Earlier in the ḥadīths we already quoted some of their statements, which indicate the position of the rest. Even without those quotations it is known that the entire ummah agrees, in principle, on the reprehensibility of imitating the People of the Book or the non-Arabs, though they may differ in certain particulars: some because they believe a given practice is not really one of the unbelievers’ customs, others because they consider the supporting evidence stronger, or for other reasons. In the same way they are united in following the Qur’an and the Sunnah, even if someone may, on occasion, depart from them on the basis of an interpretive judgment.

Allah, exalted is He, knows best.