Nafi' (may Allah have mercy on him) says that once, while in the state of Ihram, Abdullah ibn Umar (may Allah be pleased with them both) felt cold. He said to me, "Put some cloth over me." I put a cap on him, but he pushed it back and said, "You are putting on me such a cloth which the Prophet (peace and blessings of Allah be upon him) has forbidden the Muhrim to wear."