Sahih al-Bukhari 3102
Sahih al-Bukhari · Book 57: One-fifth of Booty to the Cause of Allah (Khumus) · What has been said regarding the houses of the wives of the Prophet ﷺ and that which were named after them of the houses (e.g., ‘Aishah’s house)
Narrated `Abdullah bin `Umar:
حَدَّثَنَا إِبْرَاهِيمُ بْنُ الْمُنْذِرِ ، حَدَّثَنَا أَنَسُ بْنُ عِيَاضٍ ، عَنْ عُبَيْدِ اللَّهِ ، عَنْ مُحَمَّدِ بْنِ يَحْيَى بْنِ حَبَّانَ ، عَنْ وَاسِعِ بْنِ حَبَّانَ ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ ـ رضى الله عنهما ـ قَالَ ارْتَقَيْتُ فَوْقَ بَيْتِ حَفْصَةَ، فَرَأَيْتُ النَّبِيَّ صلى الله عليه وسلم يَقْضِي حَاجَتَهُ، مُسْتَدْبِرَ الْقِبْلَةِ، مُسْتَقْبِلَ الشَّأْمِ.
Once I went upstairs in Hafsa's house and saw the Prophet (ﷺ) answering the call of nature with his back towards the Qibla and facing Sham.