Sahih Muslim
The Book Pertaining to Clothes and Decoration (Kitab Al-Libas wal-Zinah)
Book Number: 024 / Hadith Number: 5173
'Abdullah b. 'Amr b. al-As reported: Allah's Messenger (may peace be upon him) saw me wearing two clothes dyed in saffron. whereupon he said: These are the clothes (usually worn by) the non-believers, so do not wear them.