Volume 2, Book 26, Number 633:

Narrated 'Aisha: We set out with Allah's Apostles (to Mecca) in the year of the Prophet's Last Hajj. Some of us had assumed Ihram for 'Umra only, some for both Hajj and 'Umra, and others for Hajj only. Allah's Apostle assumed Ihram for Hajj. So whoever had assumed Ihram for Hajj or for both Hajj and 'Umra did not finish the Ihram till the day of sacrifice. (See Hadith No. 631, 636, and 639).

Volume 2, Book 26, Number 634:

Narrated Marwan bin Al-Hakam: I saw 'Uthman and 'Ali. 'Uthman used to forbid people to perform Hajj-at-Tamattu' and Hajj-al-Qiran (Hajj and 'Umra together), and when 'Ali saw (this act of 'Uthman), he assumed Ihram for Hajj and 'Umra together saying, "Lubbaik for 'Umra and Hajj," and said, "I will not leave the tradition of the Prophet on the saying of somebody."

Volume 2, Book 26, Number 635:

Narrated Ibn Abbas: The people (of the Pre-lslamic Period) used to think that to perform 'Umra during the months of Hajj was one of the major sins on earth. And also used to consider the month of Safar as a forbidden (i.e. sacred) month and they used to say, "When the wounds of the camel's back heal up (after they return from Hajj) and the signs of those wounds vanish and the month of Safar passes away then (at that time) 'Umra is permissible for the one who wishes to perform it." In the morning of the 4th of Dhul-Hijja, the Prophet and his companions reached Mecca, assuming Ihram for Hajj and he ordered his companions to make their intentions of the Ihram for'Umra only (instead of Hajj) so they considered his order as something great and were puzzled, and said, "O Allah's Apostle! What kind (of finishing) of Ihram is allowed?" The Prophet replied, "Finish the Ihram completely like a non-Muhrim (you are allowed everything)."

Volume 2, Book 26, Number 636:

Narrated Abu Musa: came to the Prophet (from Yemen and was assuming Ihram for Hajj) and he ordered me to finish the Ihram (after performing the 'Umra).

Volume 2, Book 26, Number 637:

Narrated Ibn 'Umar: Hafsa the wife of the Prophet said, "O Allah's Apostle! Why have the people finished their Ihram after performing 'Umra but you have not finished your Ihram after performing 'Umra?" He replied, "I have matted my hair and garlanded my Hadi. So I will not finish my Ihram till I have slaughtered (my Hadi). "

Volume 2, Book 26, Number 638:

Narrated Shu'ba: Abu Jamra Nasr bin 'Imran Ad-Duba'i said, "I intended to perform Hajj-at-Tamattu' and the people advised me not to do so. I asked Ibn Abbas regarding it and he ordered me to perform Hajj-at-Tammatu'. Later I saw in a dream someone saying to me, 'Hajj-Mabrur (Hajj performed in accordance with the Prophet's tradition without committing sins and accepted by Allah) and an accepted 'Umra.' So I told that dream to Ibn Abbas. He said, 'This is the tradition of Abu-l-Qasim.' Then he said to me, 'Stay with me and I shall give you a portion of my property.' " I (Shu'ba) asked, "Why (did he invite you)?" He (Abu Jamra) said, "Because of the dream which I had seen."

Volume 2, Book 26, Number 639:

Narrated Abu Shihab: I left for Mecca for Hajj-at-Tamattu' assuming Ihram for 'Umra. I reached Mecca three days before the day of Tarwiya (8th Dhul-Hijja). Some people of Mecca said to me, "Your Hajj will be like the Hajj performed by the people of Mecca (i.e. you will lose the superiority of assuming Ihram from the Miqat). So I went to 'Ata' asking him his view about it. He said, "Jabir bin 'Abdullah narrated to me, 'I performed Hajj with Allah's Apostle on the day when he drove camels with him. The people had assumed Ihram for Hajj-al-Ifrad. The Prophet ordered them to finish their Ihram after Tawaf round the Ka'ba, and between Safa and Marwa and to cut short their hair and then to stay there (in Mecca) as non-Muhrims till the day of Tarwiya (i.e. 8th of Dhul-Hijja) when they would assume Ihram for Hajj and they were ordered to make the Ihram with which they had come as for 'Umra only. They asked, 'How can we make it 'Umra (Tamattu') as we have intended to perform Hajj?' The Prophet said, 'Do what I have ordered you. Had I not brought the Hadi with me, I would have done the same, but I cannot finish my Ihram till the Hadi reaches its destination (i.e. is slaughtered).' So, they did (what he ordered them to do)."