Imam Aḥmad, by contrast, held that the act is forbidden and the contract does not take effect. Ibn Hubayrah states, “Aḥmad rejected both its validity and its permissibility.” In al-Furūʿ it is written: “Hiring and leasing are governed by the same rule as selling.” Al-Iqnāʿ adds: “It is unlawful to sell, buy, or lease in the mosque; should anyone do so, the transaction is null and void. It is recommended to say to whoever buys or sells there, ‘May Allah not grant your trade profit,’ so as to deter him.”

3 – Mosques were built solely for obeying and worshipping Allah, so worldly pursuits must be kept out of them. Al-Qurṭubī remarked: “Among the things from which mosques must be protected and kept pure are foul odors and reprehensible words and deeds; this is part of venerating them. The meaning of Allah’s words, ‘Allah has permitted that they be raised up…’ (al-Nūr 24:36) is that He has commanded and decreed that they be built and exalted.” Numerous ḥadiths encourage the building of mosques. The phrase “be raised up” means that they are to be honored, their status elevated, and cleansed of impurities and filth. ʿĀʾishah said, “The Messenger of Allah ﷺ ordered us to establish mosques within the neighborhoods and to keep them clean and perfumed.” Reported by Aḥmad (5854).

4 – Al-Qurṭubī further said: “Mosques must be safeguarded from buying, selling, and every sort of occupation,” for Muslim (569) narrated—through the report of Buraydah—that after the Prophet ﷺ had performed the prayer, a man stood up and announced, “Who has called for the red camel?” The Prophet ﷺ responded, “May you never find it! Mosques were only built for the purpose for which they were built.” This indicates that, in principle, nothing should be undertaken in the mosque other than prayer, remembrance, and the recitation of the Quran.