Sahih Bukhari Volume 002, Book 026, Hadith Number 629.
Narated By Anas bin Malik : Ali came to the Prophet (p.b.u.h) from Yemen (to Mecca). The Prophet asked Ali, "With what intention have you assumed Ihram?" Ali replied, "I have assumed Ihram with the same intention as that of the Prophet." The Prophet said, "If I had not the Hadi with me I would have finished the Ihram." Muhammad bin Bakr narrated extra from Ibn Juraij, "The Prophet said to Ali, "With what intention have you assumed the Ihram, O Ali?" He replied, "With the same (intention) as that of the Prophet." The Prophet said, "Have a Hadi and keep your Ihram as it is."