Sahih Bukhari Volume 3, Book 28, Hadith Number 39.

Narated By Nafi : That Abdullah and Salim said to ‘Abdullah bin ‘Umar, “(You should not go for Hajj this year).” ‘Abdullah bin ‘Umar replied, “We set out with the Prophet (to Mecca for performing ‘Umra) and e infidels of Quraish prevented us from reaching the Ka’ba. Allah’s Apostle slaughtered his Budn (camels for sacrifice) and got his head shaved.”