Bulugh al-Maram, Book 5, Hadith 722 (English)

’A’isha (RAA) narrated, ‘It is Sunnah for the one performing I'tikaf not to visit the sick, attend a funeral, or touch his wife (with sexual desire), nor have sexual intercourse with her. He should also not go out (of the mosque) except for an extreme necessity, and no I’tikaf is accepted without fasting, or without being in a congregational mosque (where Friday prayer is performed).’ Related by Abu Dawud with an acceptable chain of narrators, but scholars say that the last part (starting: ‘no I'tikaf is accepted….) is most probably the saying of ’A’isha (RAA), i.e. Hadith Mauquf (i.e. that which the companion does not connect to the Prophet and it is not the Prophet himself.

وَعَنْهَا قَالَتْ: { اَلسُّنَّةُ عَلَى اَلْمُعْتَكِفِ أَنْ لَا يَعُودَ مَرِيضًا, وَلَا يَشْهَدَ جِنَازَةً, وَلَا يَمَسَّ امْرَأَةً, وَلَا يُبَاشِرَهَا, وَلَا يَخْرُجَ لِحَاجَةٍ, إِلَّا لِمَا لَا بُدَّ لَهُ مِنْهُ, وَلَا اعْتِكَافَ إِلَّا بِصَوْمٍ وَلَا اعْتِكَافَ إِلَّا فِي مَسْجِدٍ جَامِعٍ } رَوَاهُ أَبُو دَاوُدَ, وَلَا بَأْسَ بِرِجَالِهِ, إِلَّا أَنَّ اَلرَّاجِحَ وَقْفُ آخِرِهِ 1‏.‏ ‏1 ‏- حسن.‏ رواه أبو داود ( 2473 )‏ وأعل بما لا يقدح كما تجده في " الأصل ".‏

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also referenced under: Book 5, Hadith 702 (In-Book)