Is it an innovation to forbid Itikaf (spiritual retreat) in places other than the Three Mosques (the Sacred Mosque in Mecca, the Prophet's Mosque in Medina, and Al-Aqsa Mosque in Jerusalem)? And does Allah Almighty’s saying: "while you are secluded in the mosques" indicate the permissibility of Itikaf in all mosques without exception?

It is a condition for I'tikaf (spiritual retreat) to be performed in a mosque. Scholars have agreed upon its validity in the three sacred mosques (Masjid al-Haram, Masjid al-Nabawi, Masjid al-Aqsa) and in every Jami' (congregational) mosque, although there are differences in the details of this.

- The Hanafi school stipulates that it must be in a Jami' mosque or one where the five daily prayers are performed for men. A woman performs I'tikaf in the mosque of her home as a preference.

- The Maliki school deems it valid in any mosque, unless the one performing I'tikaf is someone for whom Friday prayer is obligatory and due during their I'tikaf, in which case they must perform I'tikaf in a mosque where Friday prayer is held.

- The Shafi'i school considers I'tikaf valid for both men and women in every mosque, and invalid in the mosque of their homes.

- The Hanbali school deems I'tikaf valid in every mosque where congregational prayer is established if the one performing I'tikaf is someone for whom congregational prayer is obligatory and a prayer will occur during their I'tikaf. As for those for whom congregational prayer is not obligatory (such as a child or a woman), it is valid in any mosque.

The most preponderant opinion is the permissibility of I'tikaf in any mosque, based on the generality of Allah’s Almighty saying: "وَأَنتُمْ عَاكِفُونَ فِي الْمَسَاجِدِ" (while you are in retreat in the mosques).