Mishkat al-Masabih 22 Clothing كتاب اللباس 39

وَعَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَنْ تَشَبَّهَ بِقَوْمٍ فَهُوَ مِنْهُمْ» . رَوَاهُ أَحْمد وَأَبُو دَاوُد

He reported God’s messenger as saying, “He who copies any people is one of them.” Ahmad and Abu Dawud transmitted it.