Musnad Ahmad 28:345

Waki' narrated to us, Ali ibn al-Mubarak narrated to us, from Yahya ibn Abi Kathir, from Muhammad ibn Ibrahim, from Khalid ibn Ma'dan, from Jubayr ibn Nufayr, from Abdullah ibn Amr, who said: The Messenger of Allah (peace and blessings of Allah be upon him) saw me wearing garments dyed with safflower. He said: "Cast them off, for they are the garments of the disbelievers."