Sunan an-Nasa'i, Book 1, Hadith 137 (In-Book) ⓘ

It was narrated that Abu Hayyah said: "I saw 'Ali performing Wudu', washing each part thrice. Then he stood up and drank the water that was left over from his Wudu' and said: 'The Messenger of Allah did as I have done.'"

أَخْبَرَنَا أَبُو دَاوُدَ، سُلَيْمَانُ بْنُ سَيْفٍ قَالَ حَدَّثَنَا أَبُو عَتَّابٍ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ أَبِي إِسْحَاقَ، عَنْ أَبِي حَيَّةَ، قَالَ رَأَيْتُ عَلِيًّا - رضى الله عنه - تَوَضَّأَ ثَلاَثًا ثَلاَثًا ثُمَّ قَامَ فَشَرِبَ فَضْلَ وَضُوئِهِ وَقَالَ صَنَعَ رَسُولُ اللَّهِ صلى الله عليه وسلم كَمَا صَنَعْتُ ‏.‏