Sunan An-Nasa'i
Hadith #2635
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