The Book of Pilgrimage
15/31. Chapter:
It is permissible to perform 'Umrah during the months of Hajj
Sahih Muslim
وَحَدَّثَنَا هَارُونُ بْنُ عَبْدِ اللَّهِ، حَدَّثَنَا مُحَمَّدُ بْنُ الْفَضْلِ السَّدُوسِيُّ، حَدَّثَنَا وُهَيْبٌ، أَخْبَرَنَا أَيُّوبُ، عَنْ أَبِي الْعَالِيَةِ الْبَرَّاءِ، عَنِ ابْنِ عَبَّاسٍ، - رضى الله عنهما - قَالَ قَدِمَ النَّبِيُّ صلى الله عليه وسلم وَأَصْحَابُهُ لأَرْبَعٍ خَلَوْنَ مِنَ الْعَشْرِ وَهُمْ يُلَبُّونَ بِالْحَجِّ فَأَمَرَهُمْ أَنْ يَجْعَلُوهَا عُمْرَةً .
Ibn 'Abbas (Allah be pleased with them) reported: Allah's Messenger (ﷺ) came along with his Companions when four days had passed out of ten days (of Dhu'l-Hijja) and they were pronouncing Talbiya for Hajj, and he (the Holy Prophet) commanded them to change (this Ihram) into that of 'Umra.
Reference : Sahih Muslim 1240dIn-book reference : Book 15, Hadith 220USC-MSA web (English) reference : Book 7, Hadith 2861