Scholarly disagreement:
Imam Abu Ḥanīfah—may Allah have mercy on him—adopted an isolated view, permitting the sale of an endowment (waqf) and allowing the founder to reclaim it. His opinion conflicts with the explicit wording of the hadith, and for that reason his disciple Abū Yūsuf said, “Had Abu Ḥanīfah received this hadith—the report of ʿUmar—he would have followed it and withdrawn his ruling that a waqf may be sold.”
Al-Qurṭubī remarked, “Revoking a waqf runs counter to the consensus and is therefore of no consequence.”

Imams Mālik and al-Shāfiʿī held that once a waqf is established it becomes irrevocably binding; its sale is neither permissible nor valid under any circumstances. They relied on the general wording of the hadith, “Its principal is not to be sold….”

Imam Aḥmad took a middle position: the property may neither be sold nor exchanged unless its benefits have ceased entirely and it can no longer be used, restored, or repaired. If its benefits have indeed disappeared, then it may be sold and replaced by something else. He based this on the precedent of ʿUmar when he learned that the public treasury in Kūfah had been breached. ʿUmar wrote to Saʿd, “Move the mosque that is among the date merchants and place the treasury at the qiblah side of the mosque, for there will always remain a place for prayer in the mosque.” This step was taken in the presence of the Companions and none objected, which makes it tantamount to consensus.

Aḥmad likened the matter to a sacrificial animal (hady) that becomes incapacitated before reaching its destination: it is slaughtered on the spot, and insistence on reaching the destination is waived because that would result in complete loss of benefit.

Ibn ʿAqīl—may Allah have mercy on him—said, “A waqf is intended to last forever. If it cannot endure in the particular form specified, we preserve its objective—continuous benefit—by transferring that benefit to another asset. Conveying substitutes serves the same purpose as the original property, whereas clinging to an unusable asset frustrates the very goal.”

Shaykh al-Islām Ibn Taymiyyah—may Allah have mercy on him—stated, “When there is need, the waqf must be replaced with something equivalent; when there is no need, it may be replaced with something better, because the benefit is clearly greater.” He added that a waqf may be substituted even if it is a mosque, provided it is replaced with one similar to it or better. The same ruling applies to a sacrificial animal, an ʿīd offering, or a vowed offering: one may give an equivalent in compensation or sell the original and purchase another with the proceeds. The sole exception is the three sacred mosques—al-Masjid al-Ḥarām, the Prophet’s Mosque, and al-Masjid al-Aqṣā—whose sites may not be altered; only enlargements and rebuilding on the same site are permissible, as established by the Sunnah and the consensus of the Companions.

Our teacher ʿAbd al-Raḥmān Āl-Saʿdī—may Allah have mercy on him—said that when the endowed property suffers damage or its benefits diminish, and