Sahih Bukhari Volume 3, Book 27, Hadith 1808

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مُحَمَّدِ بْنِ أَسْمَاءَ، حَدَّثَنَا جُوَيْرِيَةُ، عَنْ نَافِعٍ، أَنَّ عُبَيْدَ اللَّهِ بْنَ عَبْدِ اللَّهِ، وَسَالِمَ بْنَ عَبْدِ اللَّهِ، أَخْبَرَاهُ أَنَّهُمَا، كَلَّمَا عَبْدَ اللَّهِ بْنَ عُمَرَ ـ رضى الله عنهما ـ لَيَالِيَ نَزَلَ الْجَيْشُ بِابْنِ الزُّبَيْرِ فَقَالاَ لاَ يَضُرُّكَ أَنْ لاَ تَحُجَّ الْعَامَ، وَإِنَّا نَخَافُ أَنْ يُحَالَ بَيْنَكَ وَبَيْنَ الْبَيْتِ‏.‏ فَقَالَ خَرَجْنَا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم فَحَالَ كُفَّارُ قُرَيْشٍ دُونَ الْبَيْتِ، فَنَحَرَ النَّبِيُّ صلى الله عليه وسلم هَدْيَهُ، وَحَلَقَ رَأْسَهُ، وَأُشْهِدُكُمْ أَنِّي قَدْ أَوْجَبْتُ الْعُمْرَةَ، إِنْ شَاءَ اللَّهُ أَنْطَلِقُ، فَإِنْ خُلِّيَ بَيْنِي وَبَيْنَ الْبَيْتِ طُفْتُ، وَإِنْ حِيلَ بَيْنِي وَبَيْنَهُ فَعَلْتُ كَمَا فَعَلَ النَّبِيُّ صلى الله عليه وسلم وَأَنَا مَعَهُ‏.‏ فَأَهَلَّ بِالْعُمْرَةِ مِنْ ذِي الْحُلَيْفَةِ، ثُمَّ سَارَ سَاعَةً، ثُمَّ قَالَ ‏"‏ إِنَّمَا شَأْنُهُمَا وَاحِدٌ، أُشْهِدُكُمْ أَنِّي قَدْ أَوْجَبْتُ حَجَّةً مَعَ عُمْرَتِي ‏"‏‏.‏ فَلَمْ يَحِلَّ مِنْهُمَا حَتَّى حَلَّ يَوْمَ النَّحْرِ، وَأَهْدَى، وَكَانَ يَقُولُ لاَ يَحِلُّ حَتَّى يَطُوفَ طَوَافًا وَاحِدًا يَوْمَ يَدْخُلُ مَكَّةَ‏

Narrated By Nafi : That Ubaidullah bin 'Abdullah and Salim bin 'Abdullah informed him that they told Ibn 'Umar when Ibn Az-Zubair was attacked by the army, saying "There is no harm for you if you did not perform Hajj this year. We are afraid that you may be prevented from reaching the Kaba." Ibn 'Umar said "We set out with Allah's Apostle and the non-believers of Quraish prevented us from reaching the Ka'ba, and so the Prophet slaughtered his Hadi and got his head shaved." Ibn 'Umar added, "I make you witnesses that I have made 'Umra obligatory for me. And, Allah willing, I will go and then if the way to Ka'ba is clear, I will perform the Tawaf, but if I am prevented from going to the Ka'ba then I will do the same as the Prophet did while I was in his company." Ibn 'Umar then assumed Ihram for Umra from Dhul-Hulaifa and proceeded for a while and said, "The conditions of 'Umra and Hajj are similar and I make you witnesses that I have made 'Umra and Hajj obligatory for myself." So, he did not finish the Ihram till the day of Nahr (slaughtering) came, and he slaughtered his Hadi. He used to say, "I will not finish the Ihram till I perform the Tawaf, one Tawaf on the day of entering Mecca (i.e. of Safa and Marwa for both 'Umra and Hajj)."