Sahih al-Bukhari 1563
صحيح البخاري#1563Sahihحَدَّثَنَا مُحَمَّدُ بْنُ بَشَّارٍ، حَدَّثَنَا غُنْدَرٌ، حَدَّثَنَا شُعْبَةُ، عَنِ الْحَكَمِ، عَنْ عَلِيِّ بْنِ حُسَيْنٍ، عَنْ مَرْوَانَ بْنِ الْحَكَمِ، قَالَ شَهِدْتُ عُثْمَانَ وَعَلِيًّا ـ رضى الله عنهما ـ وَعُثْمَانُ يَنْهَى عَنِ الْمُتْعَةِ وَأَنْ يُجْمَعَ بَيْنَهُمَا. فَلَمَّا رَأَى عَلِيٌّ، أَهَلَّ بِهِمَا لَبَّيْكَ بِعُمْرَةٍ وَحَجَّةٍ قَالَ مَا كُنْتُ لأَدَعَ سُنَّةَ النَّبِيِّ صلى الله عليه وسلم لِقَوْلِ أَحَدٍ.
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, "Labbaik for `Umra and Hajj," and said, "I will not leave the tradition of the Prophet (ﷺ) on the saying of somebody
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 25:49