Sahih Muslim 2069 c
'Asim al-Abwal reported on the authority Abu Uthman saying:
'Umar wrote to us when we were in Adharba'ijan saying: 'Utba b. Farqad, this wealth is neither the result of your own labour nor the result of the labour of your father, nor the result of the labour of your mother, so feed Muslims at their own places as you feed (members of your family and yourselves at your own residence), and beware of the life of pleasure, and the dress of the polytheists and wearing of silk garments, for Allah's Messenger (ﷺ) forbade the wearing of silk garments, but only this much, and Allah's Messenger (ﷺ) raised his. forefinger and middle finger and he joined. them (to indicate that only this much silk can be allowed in the dress of a man). 'Asim said also: This is what is recorded in the lette., (sent to us), and Zuhair raised his two fingers (to give an idea of the extent to which silk may be used).
حَدَّثَنَا أَحْمَدُ بْنُ عَبْدِ اللَّهِ بْنِ يُونُسَ، حَدَّثَنَا زُهَيْرٌ، حَدَّثَنَا عَاصِمٌ الأَحْوَلُ، عَنْ أَبِي، عُثْمَانَ قَالَ كَتَبَ إِلَيْنَا عُمَرُ وَنَحْنُ بِأَذْرَبِيجَانَ يَا عُتْبَةَ بْنَ فَرْقَدٍ إِنَّهُ لَيْسَ مِنْ كَدِّكَ وَلاَ مِنْ كَدِّ أَبِيكَ وَلاَ مِنْ كَدِّ أُمِّكَ فَأَشْبِعِ الْمُسْلِمِينَ فِي رِحَالِهِمْ مِمَّا تَشْبَعُ مِنْهُ فِي رَحْلِكَ وَإِيَّاكُمْ وَالتَّنَعُّمَ وَزِيَّ أَهْلِ الشِّرْكِ وَلَبُوسَ الْحَرِيرِ فَإِنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنْ لَبُوسِ الْحَرِيرِ ‏.‏ قَالَ ‏
"‏ إِلاَّ هَكَذَا ‏"‏ ‏.‏ وَرَفَعَ لَنَا رَسُولُ اللَّهِ صلى الله عليه وسلم إِصْبَعَيْهِ الْوُسْطَى وَالسَّبَّابَةَ وَضَمَّهُمَا قَالَ زُهَيْرٌ قَالَ عَاصِمٌ هَذَا فِي الْكِتَابِ ‏.‏ قَالَ وَرَفَعَ زُهَيْرٌ إِصْبَعَيْهِ ‏.‏