Sahih Bukhari Volume 003, Book 038, Hadith Number 510.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 38. Representation, Authorization, Business by Proxy.
Narated By 'Aisha : I twisted the garlands of the Hadis (i.e. animals for sacrifice) of Allah's Apostle with my own hands. Then Allah's Apostle put them around their necks with his own hands, and sent them with my father (to Mecca). Nothing legal was regarded illegal for Allah's Apostle till the animals were slaughtered.