سُنَنُ النَّسَائِيِّ
Sunan an-Nasa’i 136
The Book of Purification
Using Water Left Over From Wudu'
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 .
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 (ﷺ) did as I have done.'"
Sunan an-Nasa'i, 136Hasan (Darussalam)