Definition of I'tikaf, Its Ruling, and Its Etiquettes

Question:
Honorable Shaykh, we begin this session by discussing the sunnah (recommended practice) of i'tikaf (spiritual retreat in the mosque), the definition of i'tikaf, and the ruling on this i'tikaf. Honorable Shaykh?

Answer:
In the name of Allah, the Most Gracious, the Most Merciful. Praise be to Allah, Lord of the worlds, and may Allah send prayers and blessings upon our Prophet Muhammad, and upon his family and all his Companions. I'tikaf is staying in the mosque for the worship of Allah (Mighty and Majestic). It is staying in the mosque for the worship of Allah (Mighty and Majestic). One remains in the mosque day and night and does not leave it except for a human need, then returns and engages in the remembrance of Allah, prayer, and recitation of the Qur'an. He sleeps during the night in the state of i'tikaf, rises for night prayer, and remembers Allah (Mighty and Majestic) with various types of dhikr (remembrance of Allah). He increases his recitation of the Qur'an and attends the five daily prayers in congregation.
This is the Shari'ah-compliant i'tikaf: seclusion from people and devotion to the remembrance of Allah (Mighty and Majestic). I'tikaf is not valid except in a mosque. As for i'tikaf performed in other than a mosque, it is invalid (batil) because it prevents him from praying, specifically the Friday prayer and the congregational prayer. This seclusion is forbidden. Ibn 'Abbas (may Allah be pleased with them both) was asked about a man who stands in prayer at night and fasts by day, but does not attend the Friday prayer or the congregational prayer. He said, "He is in the Fire," because this is withdrawal from the Muslims and withdrawal from the mosques. This is not permissible. Therefore, the scholars stipulated that a condition of i'tikaf is that it be in a mosque where the congregational prayer is established, so that he does not cut off the congregational prayer. If he leaves for the congregational prayer five times, this contradicts i'tikaf. If he is in the mosque, the time of i'tikaf is not wasted for him, and he does not abandon the congregational prayer. It is obligatory (wajib) that i'tikaf be in a mosque.
It is prescribed (mashru') at all times. I'tikaf is prescribed at all times, but it is better in Ramadan because deeds are multiplied during the day, because deeds are multiplied in Ramadan, and because the Prophet (peace and blessings be upon him) used to perform i'tikaf in Ramadan. Initially, he used to perform i'tikaf in the middle ten days. Then, when it became clear to him that Laylat al-Qadr (the Night of Decree) was in the last ten days, he shifted to performing i'tikaf in the last ten days and continued to do so until he passed away (peace and blessings be upon him). Thus, i'tikaf is indicated by the Qur'an, in His saying: And in the Sunnah, through the actions of the Prophet (peace and blessings be upon him), his wives, his Companions, and those who came after them. The practice continued, so it is a sunnah (recommended practice) established by the Book, the Sunnah, and scholarly consensus (ijma'). It is a great act of worship. Yes.