سُنَنُ ابْنِ مَاجَهْ
Sunan Ibn Majah 375
The Book of Purification and its Sunnah
The prohibition of that (i.e., performing ablution with the leftover water)
حَدَّثَنَا مُحَمَّدُ بْنُ يَحْيَى، حَدَّثَنَا عُبَيْدُ اللَّهِ، عَنْ إِسْرَائِيلَ، عَنْ أَبِي إِسْحَاقَ، عَنِ الْحَارِثِ، عَنْ عَلِيٍّ، قَالَ كَانَ النَّبِيُّ ـ صلى الله عليه وسلم ـ وَأَهْلُهُ يَغْتَسِلُونَ مِنْ إِنَاءٍ وَاحِدٍ وَلاَ يَغْتَسِلُ أَحَدُهُمَا بِفَضْلِ صَاحِبِهِ .
It was narrated that 'Ali said: "The Prophet (ﷺ) and his wife would take a bath from one vessel, but neither of them would have a bath with the leftover water of the other." (Daif)
Sunan Ibn Majah, 375