Sahih Muslim Book 7, Hadith Number 2841.

Chapter : Permissibility of putting off Ihram (in the midst of Hajj ceremonies) in case of obstruction and permissibility of Qiran.

Nafi’ reported that Ibn Umar intended to go for Hajj during the year when Hajjaj attacked Ibn Zubair. It was said to him: There is a state of war between people and we fear that they would detain you, whereupon he (‘Abdullah b. Umar) said: “Verily in the Messenger of Allah there is a model pattern for you.” I would do as Allah’s Messenger (may peace be upon him) did. I call you as witness that I have undertaken to perform ‘Umra. He then set out until, when he reached the rear side of al-Baida’, he said: There is one command both for Hajj and Umra. so bear witness. Ibn Rumh said: I call you as witness that I have undertaken to perform my Hajj along with my Umra (i.e. I am performing both of them as Qiran), and he offered the sacrifice of animals which he had bought at Qudaid. He then proceeded pronouncing Talbiya for both of them together until he reached Mecca, He circumambulated the House and (ran) between al-Safa’ and al-Marwa and made no addition to it. He neither sacrificed the animal, nor got his head shaved, nor got his hair clipped, nor did he make anything lawful which was unlawful (due to Ihram) until it was the Day of Sacrifice (10th of Dhu’l-Hijja). He then offered sacrifice, and got his hair cut, and saw that circumambulation of Hajj and ‘Umra was complete with the first circumambulation. Ibn ‘Umar said: This is how Allah’s Messenger (may peace be upon him) had done.