وَحَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَمُحَمَّدُ بْنُ بَشَّارٍ، قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، حَدَّثَنَا شُعْبَةُ، عَنْ عَمْرِو بْنِ مُرَّةَ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، قَالَ اجْتَمَعَ عَلِيٌّ وَعُثْمَانُ - رضى الله عنهما - بِعُسْفَانَ فَكَانَ عُثْمَانُ يَنْهَى عَنِ الْمُتْعَةِ أَوِ الْعُمْرَةِ فَقَالَ عَلِيٌّ مَا تُرِيدُ إِلَى أَمْرٍ فَعَلَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم تَنْهَى عَنْهُ فَقَالَ عُثْمَانُ دَعْنَا مِنْكَ ‏.‏ فَقَالَ إِنِّي لاَ أَسْتَطِيعُ أَنْ أَدَعَكَ فَلَمَّا أَنْ رَأَى عَلِيٌّ ذَلِكَ أَهَلَّ بِهِمَا جَمِيعًا ‏.‏

Sa'id b. al-Musayyab reported that 'Ali and 'Uthman (Allah be pleased with them) met at 'Usfan; and Uthman used to forbid (people) from performing Tamattu' and 'Umra (during the period of Hajj), whereupon 'Ali said: What is your opinion about a matter which the Messenger of Allah (PBUH) did but you forbid it? Thereupon Uthman said: You leave us alone, whereupon he ('Ali) said: I cannot leave you alone. When 'Ali saw this, he put on Ihram for both of them together (both for Hajj and 'Umra). Translation Not Available

Book Ref: Sahih Muslim Book 15 Hadith 2816
Web Ref:  Sahih Muslim Book 7 Hadith 1223 c