Hadithcore
Sahih Muslim, 1229 b
sahih

Hafsa (Allah be pleased with her) reported:

I said: Messenger of Allah what is the matter with you that you have not put off Ihram? The rest of the hadith is the same.

وَحَدَّثَنَاهُ ابْنُ نُمَيْرٍ، حَدَّثَنَا خَالِدُ بْنُ مَخْلَدٍ، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، عَنْ حَفْصَةَ، - رضى الله عنهم - قَالَتْ قُلْتُ يَا رَسُولَ اللَّهِ مَا لَكَ لَمْ تَحِلَّ بِنَحْوِهِ ‏.‏

References2 variants
In-Book Reference
Book 15, Hadith 193
USC-MSA web (English) reference
Book 7, Hadith 2834 (deprecated numbering scheme)