Chapter 24: The Book of Hajj
It was narrated from Ibn 'abbas that: a woman from Khath' am asked the Prophet on the morning of the Day of Sacrifice: "O Messenger of Allah! The command of Allah to His slaves to perform Hajj has come, while my father is an old man and cannot sit firmly in the saddle. Can I perform Hajj on his behalf?" He said: "Yes. "
Sunan an-Nasa'i 2635