Sahih Muslim Book 7, Hadith Number 2801.

Chapter : Performing Hajj and Umra separately.

Abu Nadra reported: Ibn ‘Abbas commanded the performance of Mut’a putting ihram for ‘Umra during the months of Dhu’I-Hijja and after completing it, then putting on Ihram for Hajj), but Ibn Zubair forbade to do it. I made a mention of it to Jabir b. Abdullih and he said: It is through me that this Hadith has been circulated. We entered into the state of Ihram as Tamattu’ with the Messenger of Allah (may peace be upon him). When ‘Umar was Installed as Caliph, he said: Verily Allah made permissible for His Messenger (may peace be upon him) whatever He liked and as Re liked. And (every command) of the Holy Qur’an has been revealed for every occasion. So accomplish Hajj and Umra for Allah as Allah has commanded you; and confirm by (proper conditions) the marriage of those women (with whom you have performed Mut’a). And any person would come to me with a marriage of appointed duration (Mut’a), I would stone him (to death). Qatada narrated this Hadith with the same chain of transmitters saying: (That ‘Umar also said): Separate your Hajj from ‘Umra, for that is the most complete Hajj, and complete your Umra.