As for drinking: the prayer is invalidated by drinking a substantial amount, whether deliberately or forgetfully. It is not invalidated by a small amount drunk forgetfully, nor by a small amount drunk deliberately if it is a voluntary prayer. They supported this with textual evidence and reasoning.

As for the textual evidence, they said: Abdullah ibn al-Zubayr—may Allah be pleased with him and his father—would make his voluntary prayer lengthy, and at times he would become thirsty and drink a small amount (1). This is the action of a Companion, and the action of a Companion is proof when it is not contradicted by a text or by the action of another Companion.

As for the reasoning: voluntary prayer is less stringent than obligatory prayer. This is demonstrated by the fact that certain obligations are waived in voluntary prayer but not in obligatory prayer, such as standing and facing the qiblah while travelling. Since voluntary prayer is less stringent, and a person may sometimes prolong it considerably and thus need to drink, he is permitted a small amount of drinking in order to encourage him to perform voluntary prayer.

If someone were to say, “Then allow a small amount of deliberate eating as well,” we reply: No, for there is a difference between eating and drinking. Eating requires chewing and more movement, and the need for it during prayer is less. Drinking, on the other hand, does not require that, and the need for it during prayer is greater.

The apparent meaning of the author’s words, “a small amount of drinking,” is that there is no difference whether what is drunk is water, milk, juice, or the like. However, the scholars of the school said that swallowing dissolved sugar in the mouth is like eating (2).

Some of them said that it is like drinking.