and the Sunnah—whether Allah and His Messenger intended such-and-such—and people’s disagreements over subtle questions of speculative theology, such as the indivisible atom, the homogeneity of bodies, the persistence of accidents, and similar matters. None of this entails declaring anyone a disbeliever or a sinner.

They say:

Practical questions involve both knowledge and action. If error in them (1) is forgiven, then error in questions involving knowledge without action is even more deserving of forgiveness.

Some of them say:

Fundamental questions are those supported by conclusive evidence, whereas subsidiary questions (2) are those not supported by conclusive evidence.

Those critics say:

This distinction is also mistaken. Many practical questions are supported by conclusive evidence for those acquainted with it, though others may not know it. Some are conclusively established by consensus, such as the prohibition of well-known forbidden acts and the obligation of well-known duties. Yet even if a man were to deny them out of ignorance and mistaken interpretation, he would not become a disbeliever until the proof had been established against him. During Umar’s time, for example, a group of people—including Qudāma—deemed drinking (3) wine lawful and believed it was permissible for them. The Companions did not declare them disbelievers; rather, they explained their error to them, whereupon they repented and recanted.

During the Prophet’s lifetime—may Allah bless him and grant him peace—a group continued eating after dawn had risen until the white thread became distinct (4) to them from the black thread. The Prophet—may Allah bless him and grant him peace—did not hold them sinful (5), much less declare them disbelievers, even though their error was indisputable.

The same applies to Usāma ibn Zayd: he killed the Muslim man, and his error was indisputable.