4 – From ʿAbd Allah b. ʿUmar (may Allah be pleased with them both): the Messenger of Allah ﷺ said, “When the water reaches two qullas, it does not carry filth.” In another wording: “it does not become impure.” Recorded by the Four, and declared authentic by Ibn Khuzaymah, al-Ḥākim, and Ibn Ḥibbān (1).

Grade of the ḥadith
The ḥadith is ṣaḥīḥ and is known as “the ḥadith of the two qullas.”

The scholars have differed over its soundness; some judged it defective because of inconsistency in both its chain and its wording.

1. The alleged inconsistency in the chain: the narration revolves around al-Walīd b. Kathīr. It is variously reported from him through Muḥammad b. Jaʿfar b. al-Zubayr; through Muḥammad b. ʿAbbād b. Jaʿfar; sometimes through ʿUbayd Allah b. ʿAbd Allah b. ʿUmar; and at other times through ʿAbd Allah b. ʿAbd Allah b. ʿUmar.

Reply: This does not constitute a harmful inconsistency, for—assuming every version is accurate—it merely shifts from one trustworthy narrator to another. Careful examination shows the correct chain to be: al-Walīd b. Kathīr → Muḥammad b. ʿAbbād b. Jaʿfar → ʿUbayd Allah b. ʿAbd Allah b. ʿUmar the elder; and Muḥammad b. Jaʿfar b. al-Zubayr → ʿAbd Allah b. ʿAbd Allah b. ʿUmar the younger. Anyone who narrates it otherwise is mistaken.

Several transmitters have related it from Abū Usāmah on the authority of al-Walīd b. Kathīr in both forms. It also has a third route, recorded by Ibn Mājah (518), al-Ḥākim, and others, from Ḥammād b. Salamah → ʿĀṣim b. al-Mundhir → ʿAbd Allah b. ʿAbd Allah b. ʿUmar → his father. Ibn Maʿīn was asked