Sahih Bukhari Volume 4, Book 54, Hadith Number 471.

Narated By Anas bin Malik : A silken cloak was presented to the Prophet and he used to forbid the usage of silk (by men). When the people were fascinated by the cloak. he said, “By Allah in Whose Hands the life of Muhammad is, the handkerchiefs of Sad bin Mu’adh in Paradise are better than this.”