Sahih Bukhari
Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi)
Volume: 005 / Book Number: 059 / Hadith Number: 682
Narrated Ibn Abbas:
A woman from the tribe of Khath'am asked for the verdict of Allah's Apostle (regarding something) during Hajjat-ul-Wada' while Al-Fadl bin 'Abbas was the companion-rider behind Allah's Apostle. She asked, "Allah's ordained obligation (i.e. compulsory Hajj) enjoined on His slaves has become due on my old father who cannot sit firmly on the riding animal. Will it be sufficient if I perform the Hajj on his behalf?" He said, "Yes."