Sunan an-Nasa'i, Volume 3, Book 24, Hadith 2783 (DarusSalam) ⓘ
It was narrated from Hafsah, the wif3e of the Prophet, that she said: "O Messenger of Allah, why is it that the people have exited Ihram for Umrah but you have not exited your Ihram for Umrah? He said: "I have matted my hair and garlanded my Hadi, so I will not exit Ihram until I have offered the sacrifice."
أَخْبَرَنَا مُحَمَّدُ بْنُ سَلَمَةَ، قَالَ أَنْبَأَنَا ابْنُ الْقَاسِمِ، حَدَّثَنِي مَالِكٌ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، عَنْ حَفْصَةَ، زَوْجِ النَّبِيِّ صلى الله عليه وسلم أَنَّهَا قَالَتْ يَا رَسُولَ اللَّهِ مَا شَأْنُ النَّاسِ قَدْ حَلُّوا بِعُمْرَةٍ وَلَمْ تَحْلِلْ أَنْتَ مِنْ عُمْرَتِكَ قَالَ " إِنِّي لَبَّدْتُ رَأْسِي وَقَلَّدْتُ هَدْيِي فَلاَ أَحِلُّ حَتَّى أَنْحَرَ " .
also referenced under: Hadith 2781 (Reference) & Book 24, Hadith 0 (In-Book)