Musnad Abu Ya'la al-Mawsili 110:116

Bishr ibn al-Walid al-Kindi narrated to us, Sharik narrated to us, from Muhammad ibn Abd al-Rahman, the freed slave of the family of Talhah, from Kurayb, from Ibn Abbas, who said: A man came to the Prophet, may Allah bless him and grant him peace, and said: "O Messenger of Allah, my sister vowed to perform Hajj walking." He said: "Indeed, Allah has no need for the hardship of your sister. Let her perform Hajj riding, and let her offer an expiation for her oath."