Abu Dawud Book 8, Hadith Number 2572.
Chapter : Not known.
Narated By ‘Aisha, Ummul Mu’minin : while she was on a journey along with the Apostle of Allah (PBUH): I had a race with him (the Prophet) and I outstripped him on my feet. When I became fleshy, (again) I had a race with him (the Prophet) and he outstripped me. He said: This is for that outstripping.