كتاب الحج
15  
The Book of Pilgrimage
(34)
Chapter: The Ihram and Hadi of the Prophet (saws)
(34)
باب إِهْلاَلِ النَّبِيِّ صلى الله عليه وسلم وَهَدْيِهِ ‏
Sahih Muslim 1250 a

Anas (Allah be pleased with him) reported that 'Ali (Allah be pleased with him) came from the Yemen, and the Apostle (ﷺ) said:

With (what intention) have you put on Ihram? He said: I have put on Ibram in accordance with the intention with which Allah's Apostle (ﷺ) has put on Ibram, whereupon he (the Holy Prophet) said: Had there not been the sacrificial animals with me, I would have put off Ihram (after performing 'Umra).
حَدَّثَنِي مُحَمَّدُ بْنُ حَاتِمٍ، حَدَّثَنَا ابْنُ مَهْدِيٍّ، حَدَّثَنِي سَلِيمُ بْنُ حَيَّانَ، عَنْ مَرْوَانَ الأَصْفَرِ، عَنْ أَنَسٍ، - رضى الله عنه - أَنَّ عَلِيًّا، قَدِمَ مِنَ الْيَمَنِ فَقَالَ لَهُ النَّبِيُّ صلى الله عليه وسلم ‏"‏ بِمَ أَهْلَلْتَ ‏"‏ ‏.‏ فَقَالَ أَهْلَلْتُ بِإِهْلاَلِ النَّبِيِّ صلى الله عليه وسلم ‏.‏ قَالَ ‏"‏ لَوْلاَ أَنَّ مَعِيَ الْهَدْىَ لأَحْلَلْتُ ‏"‏ ‏.‏
Reference : Sahih Muslim 1250a
In-book reference : Book 15, Hadith 234
USC-MSA web (English) reference : Book 7, Hadith 2875
  (deprecated numbering scheme)