Shaykh al-Islām said:

Section

As for each person swearing that the best legal school is that of so-and-so: if each believes matters to be as he has sworn, there are two views. The stronger view is that none of them breaks his oath.

The second view is that they all break their oaths except one, whose having broken his oath remains uncertain: he may be speaking the truth. It is also possible that all the schools are equal, in which case they all break their oaths.

If all but one break their oaths, but his identity is uncertain, this resembles the case in which one of two married men says that if it is a crow, his wife is divorced, while the other says that if it is not a crow, his wife is divorced. There are two views concerning this within the school of Ahmad and elsewhere. The first is that neither man’s divorce takes effect. This is the position of al-Shāfiʿī and others. Each, however, must refrain from intercourse with his wife—according to one view, as an obligation; according to another, as a deterrent.

The second view is that divorce takes effect for one of them, just as if a single man had sworn and made the divorce apply