صحيح ابن خزيمه
Sahih Ibn Khuzaymah
جماع أبواب ذكر الماء الذي لا ينجس، والذي ينجس إذا خالطته نجاسةChapters on Water that is Pure and Impure
(91) بَابُ ذِكْرِ الدَّلِيلِ عَلَى أَنَّ تَوْقِيتَ الْمُدِّ مِنَ الْمَاءِ لِلْوُضُوءِ " أَنَّ الْوُضُوءَ بِالْمُدِّ يُجْزِئُ،Chapter 91: Evidence that specifying a mudd of water for ablution is sufficient
Hadith Q117
لَا أَنَّهُ لَا يَسَعُ الْمُتَوَضِّئُ أَنْ يَزِيدَ عَلَى الْمُدِّ أَوْ يَنْقُصَ مِنْهُ إِذْ لَوْ لَمْ يُجْزِئِ الزِّيَادَةُ عَلَى ذَلِكَ وَلَا النُّقْصَانُ مِنْهُ، كَانَ عَلَى الْمَرْءِ إِذَا أَرَادَ الْوُضُوءَ أَنْ يَكِيلَ مُدًّا مِنْ مَاءٍ فَيَتَوَضَّأَ بِهِ لَا يُبْقِي مِنْهُ شَيْئًا، وَقَدْ يَرْفُقُ الْمُتَوَضِّئُ بِالْقَلِيلِ مِنَ الْمَاءِ فَيَكْفِي بِغَسْلِ أَعْضَاءِ الْوُضُوءِ، وَيَخْرُقُ بِالْكَثِيرِ فَلَا يَكْفِي لِغَسْلِ أَعْضَاءِ الْوُضُوءِ
This does not mean that one cannot use less or more than a mudd of water for ablution. Because if it were not permissible to decrease or increase from a mudd of water, then it would become necessary for the person performing ablution to measure a mudd of water before ablution, and then perform ablution in such a way that nothing remains. Whereas sometimes the person performing ablution uses a little water carefully, and it is sufficient for washing the limbs of ablution, and sometimes more water is used carelessly, and it becomes insufficient for washing the limbs of ablution.
