Sahih Bukhari Volume 002, Book 026, Hadith Number 778.
Narated By 'Amra : I heard 'Aisha saying, "We set out (from Medina) along with Allah's Apostle five days before the end of Dhul-Qa'da with the intention of performing Hajj only. When we approached Mecca, Allah's Apostle ordered those who had no Hadi along with them to finish the lhram after performing Tawaf of the Ka'ba, (Safa and Marwa). 'Aisha added, "Beef was brought to us on the Day of Nahr and I said, 'What is this?' Somebody said, 'The Prophet has slaughtered (cows) on behalf of his wives.'"