What did the Prophet Muhammad (saw) forbid in his letter that `Umar sent to `Utba bin Farqad in Adharbijan?
 Narrated Aba `Uthman An-Nahdi:                     While we were with `Utba bin Farqad at Adharbijan, there came `Umar's letter indicating that Allah's Apostle had forbidden the use of silk except this much, then he pointed with his index and middle fingers. To our knowledge, by that he meant embroidery.