When ʿAbdullah bin ʿUmar set out for Mecca with the intentions performing ʿUmra in the period of afflictions, he said, "If I should be prevented from reaching the Kaʿba, then I would do the same as we did while in the company of Messenger of Allah ﷺ ." So, he assumed the Ihram for ʿUmra since the Prophet ﷺ had assumed the Ihram for ʿUmra in the year of Al-Hudaibiya. Then ʿAbdullah bin ʿUmar thought about it and said, "The conditions for both Hajj and ʿUmra are similar." He then turned towards his companions and said, "The conditions of both Hajj and ʿUmra are similar and I make you witnesses that I have made the performance of Hajj obligatory for myself along with ʿUmra." He then performed one Tawaf (between As-Safa and Al-Marwa) for both of them (i.e. Hajj and (ʿUmra) and considered that to be sufficient for him and offered a Hadi.
حِينَ خَرَجَ إِلَى مَكَّةَ مُعْتَمِرًا فِي الْفِتْنَةِ إِنْ صُدِدْتُ عَنِ الْبَيْتِ صَنَعْنَا كَمَا صَنَعْنَا مَعَ رَسُولِ اللَّهِ ﷺ فَأَهَلَّ بِعُمْرَةٍ مِنْ أَجْلِ أَنَّ النَّبِيَّ ﷺ كَانَ أَهَلَّ بِعُمْرَةٍ عَامَ الْحُدَيْبِيَةِ ثُمَّ إِنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ نَظَرَ فِي أَمْرِهِ فَقَالَ مَا أَمْرُهُمَا إِلاَّ وَاحِدٌ فَالْتَفَتَ إِلَى أَصْحَابِهِ فَقَالَ مَا أَمْرُهُمَا إِلاَّ وَاحِدٌ أُشْهِدُكُمْ أَنِّي قَدْ أَوْجَبْتُ الْحَجَّ مَعَ الْعُمْرَةِ ثُمَّ طَافَ لَهُمَا طَوَافًا وَاحِدًا وَرَأَى أَنَّ ذَلِكَ مُجْزِيًا عَنْهُ وَأَهْدَى