Maliks Muwatta Book 020, Hadith Number 098.

Section : Doing the Hajj for Somebody Else.

Yahya related to me from Malik from Ibn Shihab from Sulayman ibn Yasar that Abdullah ibn Abbas said, "Al-Fadl ibn Abbas was riding behind the Messenger of Allah, may Allah bless him and grant him peace, when a woman from the Khathama tribe came to him to ask him for a fatwa. Al-Fadl began to look at her, and she at him, and the Messenger of Allah, may Allah bless him and grant him peace, turned Fadl's face away to the other side. The woman said, 'Messenger of Allah, Allah's making the hajj obligatory finds my father a very old man, unable to stay firm on his riding-beast. Can I do hajj for him?', and he said, 'Yes.' This was during the farewell hajj."