Shaykh al-Islam continues: “Because the command is immediately followed by an aptly derived description, this shows that differing from the Magians is itself intended by the Lawgiver; it is the effective cause of the ruling—or one cause among others, or part of a cause—although, left unrestricted, it is most likely a complete cause. Hence, when the early Muslims realized the dislike of resembling the Magians in this and in other matters, they avoided practices traceable to Magian custom even if the Prophet ﷺ had not specifically mentioned them. Al-Marwazī relates: ‘I asked Abū ʿAbd Allāh—meaning Aḥmad ibn Ḥanbal—about shaving the nape of the neck. He replied, “That is something the Magians do, and whoever imitates a people is one of them.” …’ Al-Khallāl reports from al-Muʿtamir ibn Sulaymān al-Tamīmī: ‘Whenever my father had his hair trimmed he would not shave the back of his neck. He was asked, “Why?” He said: He disliked imitating the non-Arabs.’ At times the early scholars explained the dislike by resemblance to the People of the Book, and at other times by resemblance to the non-Arabs; both rationales are explicitly attested in the Sunnah, and the truthful, trustworthy Messenger ﷺ foretold that such resemblance would indeed occur, as we showed earlier.” (6) Reported by al-Bukhārī 10/291; Muslim 6/155; Abū Dāwūd 2/195; al-Nasāʾī 2/273; Ibn Mājah 2/381; and Aḥmad 2/240, 260, 309, 401. Al-Shawkānī writes in Nayl al-Awtār 1/105: “This hadith shows that the rationale behind legislating the use of dye and changing grey hair is to differ from the Jews and Christians. This makes the use of dye emphatically recommended. The Messenger of Allah ﷺ was meticulous about opposing the People of the Book and commanded it. The early generations devoted great attention to this Sunnah; thus biographers often say in their entries, ‘He used to dye his hair,’ or, ‘He did not dye it.’ Ibn al-Jawzī said that many Companions and Successors dyed their hair, and Aḥmad ibn Ḥanbal, after he saw …”