Narrated Abu 'Uthman: While we were at Adharbijan, 'Umar wrote to us: 'Allah's Apostle forbade wearing silk except this much. Then the Prophet approximated his two fingers (index and middle fingers) (to illustrate that) to us.' Zuhair (the sub-narrator) raised up his middle and index fingers.
— Sahih Bukhari, Volume 7, Book 72: Dress, Hadith #719
