The Prophet ﷺ used to observe i'tikaf during the last ten days of Ramadan. One year he did not observe i'tikaf. When the next year came, he observed i'tikaf for twenty nights (i.e. days).  

أَنَّ النَّبِيَّ ﷺ كَانَ يَعْتَكِفُ الْعَشْرَ الأَوَاخِرَ مِنْ رَمَضَانَ فَلَمْ يَعْتَكِفْ عَامًا فَلَمَّا كَانَ الْعَامُ الْمُقْبِلُ اعْتَكَفَ عِشْرِينَ لَيْلَةً  

When the Messenger of Allah ﷺ intended to observe I'tikaf, he prayed the fajr prayer and then entered his place of seclusion. Once he intended to observe I'tikaf during the last ten days of Ramadan. She said: He ordered to pitch a tent for him, and it was pitched. She said: The other wives of the Prophet ﷺ also ordered to pitch tents for them and they were pitched. When he offered the fajr prayer, he saw the tents, and said: What is this ? Did you intend to do an act of virtue ? She said: He then ordered to demolish his tent, and it was demolished. Then his wives also ordered to demolish their tents and they were demolished. He then postponed I'tikaf till the first ten days, that is of Shawwal. Abu Dawud said: This tradition has been transmitted by Ibn Ishaq and al-Auza'i from Yahya b. Sa'id in a similar manner, and Malik narrated it from Yahya b. Sa'id, saying: He observed I'tikaf during twenty days of Shawwal.  

كَانَ رَسُولُ اللَّهِ ﷺ إِذَا أَرَادَ أَنْ يَعْتَكِفَ صَلَّى الْفَجْرَ ثُمَّ دَخَلَ مُعْتَكَفَهُ قَالَتْ وَإِنَّهُ أَرَادَ مَرَّةً أَنْ يَعْتَكِفَ فِي الْعَشْرِ الأَوَاخِرِ مِنْ رَمَضَانَ قَالَتْ فَأَمَرَ بِبِنَائِهِ فَضُرِبَ فَلَمَّا رَأَيْتُ ذَلِكَ أَمَرْتُ بِبِنَائِي فَضُرِبَ قَالَتْ وَأَمَرَ غَيْرِي مِنْ أَزْوَاجِ النَّبِيِّ ﷺ بِبِنَائِهِ فَضُرِبَ فَلَمَّا صَلَّى الْفَجْرَ نَظَرَ إِلَى الأَبْنِيَةِ فَقَالَ مَا هَذِهِ آلْبِرَّ تُرِدْنَ قَالَتْ فَأَمَرَ بِبِنَائِهِ فَقُوِّضَ وَأَمَرَ أَزْوَاجُهُ بِأَبْنِيَتِهِنَّ فَقُوِّضَتْ ثُمَّ أَخَّرَ الاِعْتِكَافَ إِلَى الْعَشْرِ الأُوَلِ يَعْنِي مِنْ شَوَّالٍ  

The Prophet ﷺ used to observe I'tikaf during the last ten days of Ramadan. Nafi' said: 'Abd Allah (b. 'Umar) showed me the place in the mosque where Messenger of Allah ﷺ used to observe I'tikaf.  

أَنَّ النَّبِيَّ ﷺ كَانَ يَعْتَكِفُ الْعَشْرَ الأَوَاخِرَ مِنْ رَمَضَانَ قَالَ نَافِعٌ وَقَدْ أَرَانِي عَبْدُ اللَّهِ الْمَكَانَ الَّذِي يَعْتَكِفُ فِيهِ رَسُولُ اللَّهِ ﷺ مِنَ الْمَسْجِدِ  

The Prophet ﷺ used to observe I'tikaf during ten days of Ramadan every year. But when the year in which he died, he observed I'tikaf for twenty days.  

كَانَ النَّبِيُّ ﷺ يَعْتَكِفُ كُلَّ رَمَضَانَ عَشَرَةَ أَيَّامٍ فَلَمَّا كَانَ الْعَامُ الَّذِي قُبِضَ فِيهِ اعْتَكَفَ عِشْرِينَ يَوْمًا  

When the Messenger of Allah ﷺ 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).  

كَانَ رَسُولُ اللَّهِ ﷺ إِذَا اعْتَكَفَ يُدْنِي إِلَىَّ رَأْسَهُ فَأُرَجِّلُهُ وَكَانَ لاَ يَدْخُلُ الْبَيْتَ إِلاَّ لِحَاجَةِ الإِنْسَانِ  

And Yunus also narrated in a similar way from al-Zuhri, and no one supported Malik in his narration from 'Urwah from 'Umrah ; and Ma'mar, Ziyad b. Sad and others have also narrated it from al-Zuhri from 'Urwah on the authority of 'Aishah.  

عَنِ النَّبِيِّ ﷺ نَحْوَهُ  

The Messenger of Allah ﷺ used to observe I'tikaf in the mosque and put his head near me through the opening of the apartment, and I would wash his head. Musaddad said: "And I would comb it while I was menstruating."  

كَانَ رَسُولُ اللَّهِ ﷺ يَكُونُ مُعْتَكِفًا فِي الْمَسْجِدِ فَيُنَاوِلُنِي رَأْسَهُ مِنْ خَلَلِ الْحُجْرَةِ فَأَغْسِلُ رَأْسَهُ وَقَالَ مُسَدَّدٌ فَأُرَجِّلُهُ وَأَنَا حَائِضٌ  

When the Messenger of Allah ﷺ was observing I'tikaf (in the mosque), I would come to him to visit him. I had a talk with him and then stood up. I then returned and he (the Prophet) also stood up to accompany me (to my house). Her dwelling place was in the house of Usamah b. Zaid. Two men from the Ansar (helpers) passed (by him at the moment). When they saw the Prophet ﷺ, they walked quickly. The Prophet ﷺ said: Be at ease, she is Safiyyah daughter of Huyayy. They said: Be glory to Allah, Messenger of Allah! He said: Satan runs in man like blood. I feared he might inspire something in your mind, or he said: evil (the narrator doubted).  

كَانَ رَسُولُ اللَّهِ ﷺ مُعْتَكِفًا فَأَتَيْتُهُ أَزُورُهُ لَيْلاً فَحَدَّثْتُهُ ثُمَّ قُمْتُ فَانْقَلَبْتُ فَقَامَ مَعِي لِيَقْلِبَنِي وَكَانَ مَسْكَنُهَا فِي دَارِ أُسَامَةَ بْنِ زَيْدٍ فَمَرَّ رَجُلاَنِ مِنَ الأَنْصَارِ فَلَمَّا رَأَيَا النَّبِيَّ ﷺ أَسْرَعَا فَقَالَ النَّبِيُّ ﷺ عَلَى رِسْلِكُمَا إِنَّهَا صَفِيَّةُ بِنْتُ حُيَىٍّ قَالاَ سُبْحَانَ اللَّهِ يَا رَسُولَ اللَّهِ قَالَ إِنَّ الشَّيْطَانَ يَجْرِي مِنَ الإِنْسَانِ مَجْرَى الدَّمِ فَخَشِيتُ أَنْ يَقْذِفَ فِي قُلُوبِكُمَا شَيْئًا أَوْ قَالَ شَرًّا  

The tradition mentioned above has also been transmitted by Al Zuhri through a different chain of narrators. In this version she said “When he was at the gate of the mosque which was near the gate of Umm Salamah, two men passed them. The narrator then transmitted the tradition to the same effect.  

حَتَّى إِذَا كَانَ عِنْدَ بَابِ الْمَسْجِدِ الَّذِي عِنْدَ بَابِ أُمِّ سَلَمَةَ مَرَّ بِهِمَا رَجُلاَنِ وَسَاقَ مَعْنَاهُ  

According to the version of Al Nufaili, A’ishah said “The Prophet ﷺ used to pass by a patient while he was observing I’tikaf(in the mosque) but he passed as usual and did not stay asking about him.” According to the version of Ibn Isa she said “The Prophet ﷺ would visit a patient while he was observing I’tikaf.”  

كَانَ النَّبِيُّ ﷺ يَمُرُّ بِالْمَرِيضِ وَهُوَ مُعْتَكِفٌ فَيَمُرُّ كَمَا هُوَ وَلاَ يُعَرِّجُ يَسْأَلُ عَنْهُ وَقَالَ ابْنُ عِيسَى قَالَتْ إِنْ كَانَ النَّبِيُّ ﷺ يَعُودُ الْمَرِيضَ وَهُوَ مُعْتَكِفٌ  

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.  

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  

Umar (may Allah be pleased with him) took a vow in the pre-Islamic days to spend a night or a day in devotion near the Ka'bah (in the sacred mosque). He asked the Prophet ﷺ about it. He said: Observe i'tikaf (i.e. spend a night or a day near the Ka'bah) and fast.  

أَنَّ عُمَرَ ؓ جَعَلَ عَلَيْهِ أَنْ يَعْتَكِفَ فِي الْجَاهِلِيَّةِ لَيْلَةً أَوْ يَوْمًا عِنْدَ الْكَعْبَةِ فَسَأَلَ النَّبِيَّ ﷺ فَقَالَ اعْتَكِفْ وَصُمْ  

The tradition mentioned above (No. 2468) has also been transmitted by Abdullah ibn Budayl through a different chain of narrators in a similar way. This version adds: While he (Umar) was observing i'tikaf (in the sacred mosque), the people uttered (loudly): "Allah is most great." He said: What is this, Abdullah? He said: These are the captives of the Hawazin whom the Messenger of Allah ﷺ has set free. He said: This slave-girl too? He sent her along with them.  

فَبَيْنَمَا هُوَ مُعْتَكِفٌ إِذْ كَبَّرَ النَّاسُ فَقَالَ مَا هَذَا يَا عَبْدَ اللَّهِ قَالَ سَبْىُ هَوَازِنَ أَعْتَقَهُمُ النَّبِيُّ ﷺ قَالَ وَتِلْكَ الْجَارِيَةُ فَأَرْسَلَهَا مَعَهُمْ  

A’ishah(may Allaah be pleased with her) said “One of the wives of the Apostle of Allaah ﷺ observed I’tikaf along with him (in the mosque). She would see yellowness and redness. Sometimes we would place a washbasin while she prayed.”  

قَالَتِ اعْتَكَفَتْ مَعَ النَّبِيِّ ﷺ امْرَأَةٌ مِنْ أَزْوَاجِهِ فَكَانَتْ تَرَى الصُّفْرَةَ وَالْحُمْرَةَ فَرُبَّمَا وَضَعْنَا الطَّسْتَ تَحْتَهَا وَهِيَ تُصَلِّي