Sahih Muslim Book 7, Hadith Number 2799.

Chapter : Types of Ihram- It is permissible to enter into the state of Ihram singularly for the sake of Hajj or for tamattu’ bi’l-‘umra ila’l-Hajj or for both hajj and ‘umra together.

Musa b. Nafi reported: I came to Mecca as a Mutamattil for Umra (performing Umra first and then putting off ihram and again entering into the state of Ihram for Hajj) four days before the day of Tarwiya (i.e. on tee 4th of Dhu’l-Hijja). Thereupon the people said: Now yours is the Hajj of the Meccans. I went to ‘Ata’ b. Abi Rabah and asked his religious verdict. Ata’ said: Jabir b. ‘Abdullah al’Ans-ari (Allah be pleased with them) narrated to me that he performed Hajj with the Messenger of Allah (may peace be upon him) in the year when he took sacrificial animals with him (i.e. during the 10th year of Hijra known as the Farewell Pilgrimage) and they had put on Ihram for Hajj only (as Mufrid). The Messenger of Allah (may peace be upon him) said: Put off Ihram and circumambulate the House, and (run) between al-Safa and al-Marwa and get your hair cut and stay as non-Muhrims. When it was the day of Tarwiya, then put on Ihram for Hajj and make ihram for Mut’a (you had put on Ihram for Hajj, but take it off after performing Umra and then again put on Ihram for Hajj). They said: How should we make it Mut’a although we entered upon ihram in the name of Hajj? He said: Do whatever I command you to do. Had I not brought sacrificial animals with me, I would have done as I have commanded you to do. But it is not permissible for me to put off Ihram till the sacrifice is offered. Then they also did accordingly.