(a) Abd Khayr said: I saw Sayyiduna Ali (may Allah be pleased with him) perform ablution and wipe, then he said: "Had I not seen the Messenger of Allah (peace and blessings be upon him) wiping over the top of the feet, I would have thought that their lower part, or inner part, was more deserving of it." The two authors of the Sahih did not use Abd Khayr as evidence. This, and what is narrated with the same meaning, refers only to the feet of the khuff (leather sock), as indicated by what has preceded and by what we have narrated from Khalid bin Alqamah, from Abd Khayr, from Ali: (b) Sayyiduna Ali (may Allah be pleased with him), describing the method of the ablution of the Prophet (peace and blessings be upon him), stated that he (peace and blessings be upon him) washed his feet three times each.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1390