Sunan Ibn Majah 456
سنن ابن ماجه#456SahihIt was narrated that Abu Haiyah said:"I saw 'Ali performing ablution and he washed his feet up to the ankles, then he said: 'I wanted to show you how your Prophet purified himself
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Zubair Ali ZaiSahih
In-book reference: 1:190