Yahya related to me from Malik from Ibn Shihab from Sulayman ibnYasar that Abdullah ibn Abbas said, "Al-Fadl ibn Abbas was ridingbehind the Messenger of Allah, may Allah bless him and grant himpeace, when a woman from the Khathama tribe came to him to ask him fora fatwa. Al-Fadl began to look at her, and she at him, and theMessenger of Allah, may Allah bless him and grant him peace, turnedFadl's face away to the other side. The woman said, 'Messenger ofAllah, Allah's making the hajj obligatory finds my father a very oldman, unable to stay firm on his riding-beast. Can I do hajj for him?',and he said, 'Yes.' This was during the farewell hajj."
USC-MSA web (English) reference: Book 20, Hadith 98
Arabic reference: Book 20, Hadith 800