Sunan Abi Dawud, Hadith 42 ⓘ
Narrated Aisha, Ummul Mu'minin: The Prophet urinated and Umar was standing behind him with a jug of water. He said: What is this, Umar? He replied: Water for you to perform ablution with. He said: I have not been commanded to perform ablution every time I urinate. If I were to do so, it would become a sunnah.
حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، وَخَلَفُ بْنُ هِشَامٍ الْمُقْرِئُ، قَالاَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يَحْيَى التَّوْأَمُ، ح وَحَدَّثَنَا عَمْرُو بْنُ عَوْنٍ، قَالَ أَخْبَرَنَا أَبُو يَعْقُوبَ التَّوْأَمُ، عَنْ عَبْدِ اللَّهِ بْنِ أَبِي مُلَيْكَةَ، عَنْ أُمِّهِ، عَنْ عَائِشَةَ، قَالَتْ بَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَامَ عُمَرُ خَلْفَهُ بِكُوزٍ مِنْ مَاءٍ فَقَالَ " مَا هَذَا يَا عُمَرُ " . فَقَالَ هَذَا مَاءٌ تَتَوَضَّأُ بِهِ . قَالَ " مَا أُمِرْتُ كُلَّمَا بُلْتُ أَنْ أَتَوَضَّأَ وَلَوْ فَعَلْتُ لَكَانَتْ سُنَّةً " .
also referenced under: Hadith 42 (DarusSalam) & Book 1, Hadith 42 (USC-MSA)