do not need to base their position on this premise.
Abū al-Khattāb said:
“This is what analogy dictates concerning vows: if someone vows to pray in a particular mosque, he is bound to do so there. We depart from this only because of the revealed ruling expressed in the Prophet’s words, peace and blessings be upon him: ‘Journeys are not to be undertaken except to three mosques.’”
He was asked: “Then if someone vows to pray in al-Masjid al-Aqsā, may he pray in the Sacred Mosque instead?”
He replied:
“If the report to that effect is not authentic, we do not concede this according to this reported position.”
What Abū al-Khattāb said contradicts not only Ahmad’s explicit statements and the position of the majority of his followers, but also his other principles. According to Ahmad, the permissibility of substitution does not depend on the animal remaining in its owner’s ownership; indeed, ownership has no bearing on whether substitution is permissible. If someone vows to free a slave and designates a particular one, it is unquestionably impermissible to substitute another, even though the slave has not passed out of his ownership.
Indeed, he also holds that the Eid sacrifice has passed out of its owner’s ownership, yet it may be exchanged for a better one. We say the same concerning mosques, just as we permit substitution in things pledged by vow. Slaughtering a sacrifice is an act of worship devoted to Allah, and slaughtering a better animal is more beloved to Allah Most High. This is therefore like replacing something pledged by vow with something better, which is also better for the people of the Sacred Precinct. Emancipation is different: the slave himself is entitled to it, and substituting another would extinguish his right.
The disagreement over whether an Eid sacrifice designated by vow remains its owner’s property or passes out of his ownership and belongs to Allah resembles the disagreement concerning an endowment for a public purpose. The well-known position in Ahmad’s school, and that of the majority, is that such property belongs to Allah.
It may also be said that it belongs to the Muslim community. Those who may effect its transfer are the Muslims entitled to benefit from it; they act by virtue of custodial authority, not ownership.