31 – ʿAlī (may Allah be pleased with him) described the Prophet’s ablution, saying: “He wiped over his head once.” The report was recorded by Abū Dāwūd, al-Nasāʾī and al-Tirmidhī with an authentic chain, and al-Tirmidhī added, “It is the most reliable narration on the subject.”⦗1⦘

Hadith grading
This ḥadith is sound. All three compilers cited it with a trustworthy chain, and al-Tirmidhī declared it “the soundest report in the chapter.” Ibn ʿAbd al-Hādī remarked in al-Muḥarrar: “Its transmitters are truthful, and each of them is referenced in the Ṣaḥīḥ.” Abū Dāwūd transmitted the narration through six different routes. Similar wording is also reported from Salamah b. al-Akwāʿ, ʿAbd Allāh b. Abī Awfā and Anas. Al-Ḥāfiẓ judged its chain acceptable.

Vocabulary notes
• “Wiped” (masaha): the verb is inherently transitive; the preposition bi- that follows is stylistically superfluous, serving to emphasize that the wiping encompassed the entire head. Grammarians observe that the sense of physical contact is inseparable from the bi- in all its usages, and here it conveys precisely that meaning.