and for this reason, the scholars have said: an ancient mosque is superior to a newer mosque, because worship was established in it earlier.
Yet there is some reservation about this. We therefore say: if he designates a mosque because of a legally recognized merit, he may not substitute for it one that is inferior in that particular merit. For this reason, they said: if he designates a congregational mosque, and his period of i‘tikāf includes a Friday, then a mosque in which the Friday prayer is not held does not suffice for him. This is because the congregational mosque has the merit that the Friday prayer is held there, so that the person observing i‘tikāf does not need to leave for another mosque; and because gathering for prayer in that mosque results in a larger congregation.
The correct view in this matter is that, with regard to mosques other than the three mosques, designating one does not make it binding unless it possesses a legally recognized merit. In that case, it does become binding, because a vow must be fulfilled and it is not permissible to turn to something inferior.
If he designates the superior one, an inferior one does not suffice; conversely, if he designates the inferior one, the superior one does suffice.
His statement, “If he designates the superior one, an inferior one does not suffice; conversely, if he designates the inferior one, the superior one does suffice,” means that if he designates the superior of these mosques, an inferior one does not suffice for him. Thus, if he designates the Sacred Mosque, neither the Prophet’s Mosque in Medina nor al-Aqsa Mosque suffices. If he designates the Prophet’s Mosque in Medina, then it is valid to perform it there or in the Sacred Mosque in Mecca. If he designates al-Aqsa Mosque, then it is valid to perform it there, in Medina, or in the Sacred Mosque. This is why he said, “Conversely, if he designates the inferior one, the superior one does suffice”—that is, whoever vows to perform it in an inferior mosque may do so in a superior one.
The evidence for this is that, on the day the Prophet, peace and blessings be upon him, conquered Mecca, a man came and said, “I vowed that, if Allah granted you victory over Mecca, I would pray in the House...”