Abu Dawud Book 15, Hadith Number 3290.
Chapter : Not known.
Narated By Abdullah ibn Abbas : A man came to Prophet (PBUH) and said: Apostle of Allah, my sister has taken a vow to perform hajj on foot. The Prophet (PBUH) said: Allah gets no good from the affliction your sister imposed on herself, so let her perform hajj riding and make atonement for her oath.