مختصر صحيح بخاري
Mukhtasar Sahih Bukhari
I'tikaf in the last ten days of Ramadan (is Sunnah) and can be done in any mosque.
Narrated from Umm al-Mu'mineen Aisha Siddiqa (may Allah be pleased with her), the wife of the Noble Prophet (peace and blessings be upon him), that the Noble Prophet (peace and blessings be upon him) used to observe i'tikaf continuously during the last ten days of Ramadan, until Allah Almighty caused him (peace and blessings be upon him) to pass away. Then, after him (peace and blessings be upon him), his wives observed i'tikaf.
Mu'takif should not leave home except for necessity.
Umm al-Mu'mineen Aisha Siddiqa (may Allah be pleased with her) says: Indeed, the Messenger of Allah (peace and blessings be upon him) would lean his head towards me while he was in the mosque (in i'tikaf), so I would comb his hair, and when he (peace and blessings be upon him) was in i'tikaf, he would not enter the house except for a need.
I'tikaf only at night.
It is narrated from Amir al-Mu'minin Sayyiduna Umar bin Khattab (may Allah be pleased with him) that he asked the Noble Prophet (peace and blessings be upon him): "In the days of ignorance, I made a vow that I would perform i'tikaf for one night in the Ka'bah (so should I fulfill this vow or not?)" The Prophet (peace and blessings be upon him) said: "Fulfill your vow."
Setting up tents in the mosque.
Narrated from Umm al-Mu'mineen Aisha Siddiqa (may Allah be pleased with her) that the Prophet Muhammad (peace be upon him) intended to perform i'tikaf. When he (peace be upon him) reached the place where he intended to perform i'tikaf, he (peace be upon him) saw several tents. The tent of Umm al-Mu'mineen Aisha (may Allah be pleased with her), the tent of Umm al-Mu'mineen Hafsa (may Allah be pleased with her), and the tent of Umm al-Mu'mineen Zainab (may Allah be pleased with her). So he (peace be upon him) said: "Do you consider this as righteousness?" After that, he (peace be upon him) returned and did not perform i'tikaf, and (instead) performed i'tikaf for ten days in Shawwal.
Can the mu'takif go to the mosque door for needs?
Umm al-Mu'mineen Safiyyah (may Allah be pleased with her), the wife of the Prophet (peace and blessings of Allah be upon him), narrates that she came to visit the Messenger of Allah (peace and blessings of Allah be upon him) in the mosque during his i'tikaf, in the last ten days of Ramadan. She sat with him for a while and talked, then got up to leave. The Messenger of Allah (peace and blessings of Allah be upon him) stood up to escort her, and when she reached the door of the mosque, near the door of Umm al-Mu'mineen Umm Salamah (may Allah be pleased with her), two men from the Ansar passed by. They greeted the Messenger of Allah (peace and blessings of Allah be upon him), and he said to them: "Wait! This is Safiyyah bint Huyayy." They said, "Glory be to Allah, O Messenger of Allah! (Could we ever think ill of you?)" and this was hard for them. The Prophet (peace and blessings of Allah be upon him) said: "Satan circulates in the human body like blood, and I feared that he might cast some evil thought into your hearts."
I'tikaf in the middle ten days of Ramadan is also reported.
Narrated Abu Huraira (may Allah be pleased with him): The Prophet (peace and blessings of Allah be upon him) used to observe I'tikaf for ten days in every Ramadan, but when the year of his death came, he observed I'tikaf for twenty days.