أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا خَالِدٌ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ مُطَرِّفٍ، عَنْ عِمْرَانَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم جَمَعَ بَيْنَ حَجٍّ وَعُمْرَةٍ ثُمَّ لَمْ يَنْزِلْ فِيهَا كِتَابٌ وَلَمْ يَنْهَ عَنْهُمَا النَّبِيُّ صلى الله عليه وسلم قَالَ فِيهِمَا رَجُلٌ بِرَأْيِهِ مَا شَاءَ ‏.‏

It was narrated from 'Imran: That the Messenger of Allah combined Hajj and "Umrah, then no Qur'an was revealed concerning that, and the Prophet did not forbid it, regardless of what one man may say. Translation Not Available

Book Ref: Sunan An Nisai Book 24 Hadith 2727
Web Ref:  Sunan An Nisai Vol 3 Book 24 Hadith 2728