Others, however, held that iʿtikāf is permissible in any mosque whatsoever. This is the position of al-Shāfiʿī, Abū Ḥanīfah, and al-Thawrī, and it is the well-known view within the Mālikī school.

A second view states that iʿtikāf is valid only in a mosque where the Friday congregational prayer is held; this is the opinion transmitted by Ibn ʿAbd al-Ḥakam from Mālik.

The scholars are unanimously agreed that, as a rule, iʿtikāf must take place in a mosque, save for two exceptions: Ibn Lubābah, who deemed it sound outside a mosque and therefore maintained that marital intimacy is forbidden to the devotee only when his retreat is inside a mosque; and Abū Ḥanīfah, who held that a woman’s iʿtikāf is confined to the prayer-space within her own home.

The root of their disagreement over making a mosque a condition lies in the possible inference contained in the Almighty’s words: “Do not approach them while you are secluded in the mosques” (al-Baqarah 2:187). Does this verse carry an implicative meaning (dalīl al-khiṭāb) or not?

• Those who answered in the affirmative said: “There is no iʿtikāf except in a mosque, and whoever undertakes iʿtikāf must abstain from conjugal relations.”
• Those who denied such an implication replied: “The verse merely indicates that iʿtikāf may also be performed outside a mosque and that intimacy is not thereby prohibited; if someone were to say, ‘Do not give so-and-so anything when he is inside the house,’ the literal implication would obligate giving him something when he is outside the house.” This, however, is an isolated stance, for the majority hold that seclusion is linked to mosques precisely because a mosque is one of its conditions.

Their dispute over restricting iʿtikāf to certain mosques or allowing it in all mosques results from the clash between the general wording of the verse and an analogical argument that limits that generality.

• Whoever gave priority to the general wording said: “Iʿtikāf is valid in every mosque, in keeping with the plain sense of the verse.”
• Whoever inclined to qualifying that generality by analogy required that the mosque either host the Friday prayer—so that the devotee would not have to leave his retreat to attend Friday prayer—or be one of the mosques to which journeys are undertaken, such as the Prophet’s Mosque, in which he, peace and blessings be upon him, himself performed iʿtikāf. Other mosques were not included because they do not share its sanctity.

Their disagreement over a woman’s iʿtikāf is likewise a contest between analogy and transmitted evidence. It is authentically reported that “Hafsah, ʿĀʾishah, and Zaynab—the wives of the Prophet, peace and blessings be upon him—sought permission from the Messenger of Allah to make iʿtikāf in the mosque, and he granted it after they had pitched their tents therein.” This report proves that a woman may observe iʿtikāf in the mosque.

The opposing analogy compares iʿtikāf to ritual prayer: since a woman’s prayer in her home is superior to her prayer in the mosque, it follows that her iʿtikāf at home should likewise be preferable. Hence it is said that a woman may only perform iʿtikāf in the mosque when accompanied by her husband, following the precedent of the Prophet’s wives—peace and blessings be upon him—who secluded themselves alongside him, just as she may travel with him but not alone. This represents an attempt to reconcile analogy with the transmitted report.

As for the time span of iʿtikāf, it is not—