Sunan Abi Dawud, Hadith 2461

'Aishah said: When the Messenger of Allah observed I'tikaf, he would put his head near me, and I would comb it. and he entered the house only to fulfill human needs (i.e. to urinate or to relieve himself).

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، عَنْ مَالِكٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عُرْوَةَ بْنِ الزُّبَيْرِ، عَنْ عَمْرَةَ بِنْتِ عَبْدِ الرَّحْمَنِ، عَنْ عَائِشَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم إِذَا اعْتَكَفَ يُدْنِي إِلَىَّ رَأْسَهُ فَأُرَجِّلُهُ وَكَانَ لاَ يَدْخُلُ الْبَيْتَ إِلاَّ لِحَاجَةِ الإِنْسَانِ ‏.‏

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also referenced under: Hadith 2467 (DarusSalam)