Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
abudawud:2473And Hb b. Baqiyyah > Khālid > ʿAbd al-Raḥman / Ibn Isḥāq > al-Zuhrī > ʿUrwah > ʿĀʾishah > al-Sunnah > al-Muʿtakif

The sunnah for one who is observing i'tikaf (in a mosque) is not to visit a patient, or to attend a funeral, or touch or embrace one's wife, or go out for anything but necessary purposes. There is no i'tikaf without fasting, and there is no i'tikaf except in a congregational mosque.  

أبو داود:٢٤٧٣حَدَّثَنَا وَهْبُ بْنُ بَقِيَّةَ أَخْبَرَنَا خَالِدٌ عَنْ عَبْدِ الرَّحْمَنِ يَعْنِي ابْنَ إِسْحَاقَ عَنِ الزُّهْرِيِّ عَنْ عُرْوَةَ عَنْ عَائِشَةَ أَنَّهَا قَالَتِ السُّنَّةُ عَلَى الْمُعْتَكِفِ

أَنْ لاَ يَعُودَ مَرِيضًا وَلاَ يَشْهَدَ جَنَازَةً وَلاَ يَمَسَّ امْرَأَةً وَلاَ يُبَاشِرَهَا وَلاَ يَخْرُجَ لِحَاجَةٍ إِلاَّ لِمَا لاَ بُدَّ مِنْهُ وَلاَ اعْتِكَافَ إِلاَّ بِصَوْمٍ وَلاَ اعْتِكَافَ إِلاَّ فِي مَسْجِدٍ جَامِعٍ  

قَالَ أَبُو دَاوُدَ غَيْرُ عَبْدِ الرَّحْمَنِ بْنِ إِسْحَاقَ لاَ يَقُولُ فِيهِ قَالَتِ السُّنَّةُ قَالَ أَبُو دَاوُدَ جَعَلَهُ قَوْلَ عَائِشَةَ