If, on the other hand, the water has not changed in color, taste, or smell because of the impurity and the amount is large (1), there is likewise unanimous agreement that it retains its purifying quality.

If it is small in quantity and has not changed, Abu Hurayrah, Ibn ʿAbbās, al-Hasan al-Baṣrī, Ibn al-Musayyib, al-Thawrī, Dāwūd, Mālik, and al-Bukhārī held that it does not become impure. Al-Bukhārī even marshalled several hadiths in rebuttal of those who claimed it was impure.

By contrast, Ibn ʿUmar, Mujāhid, as well as the Hanafis, Shāfiʿis, and Hanbalis maintained that such water is rendered impure the very moment the impurity meets it—so long as the quantity is small—even if no perceptible change occurs. They cited various proofs, among them the hadith at hand; yet every one of those proofs can be answered.

The first group, meanwhile, relied on numerous evidences, including the report graded fair by al-Tirmidhī and recorded by Abū Dāwūd: “Water is pure; nothing defiles it.” They responded to the present hadith by saying that the Prophet’s prohibition was meant to prevent repulsion and harm to those who draw or drink the water, not to declare it impure. The correct view is that of the first group: impurity hinges on tangible alteration; whether the water is little or much is irrelevant. This was also the choice of Shaykh al-Islām Ibn Taymiyyah—may Allah have mercy on him.

From this, we also learn that the stronger opinion is that water in which a person has bathed after major ritual impurity (janābah) remains purifying even when the amount is small, contrary to the well-known position in our school and that of al-Shāfiʿī, which holds that such bathing strips the water of its purifying capacity so long as it is little.

Points derived from the hadith

1. The prohibition—indeed the sin—of urinating in non-flowing water. Defecation is even more emphatically forbidden, whether the water be little or much. Vast bodies of water are excluded, for mere contact with impurity does not defile them, and they may still be used for many needs other than ritual purification from minor or major states.
2. The prohibition of bathing by immersing oneself in standing water, especially for someone in a state of major ritual impurity, even if he has not urinated in it, as Muslim’s version makes clear. What is prescribed is to scoop the water out and pour it over oneself.
3. All of this is permissible in running water, although it is better to refrain from it.
4. Anything that causes harm or constitutes an act of aggression is likewise forbidden.