مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 368
Purification
How to act when relieving oneself - Section 3
وَعَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ: بَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَقَامَ عُمَرُ خَلْفَهُ بِكُوزٍ مِنْ مَاءٍ فَقَالَ: مَا هَذَا يَا عمر؟ قَالَ: مَاءٌ تَتَوَضَّأُ بِهِ. قَالَ: مَا أُمِرْتُ كُلَّمَا بُلْتُ أَنْ أَتَوَضَّأَ وَلَوْ فَعَلْتُ لَكَانَتْ سُنَّةً «.» رَوَاهُ أَبُو دَاوُد وَابْن مَاجَه
‘A'isha told of God’s messenger passing water and ‘Umar 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 pass water. If I were to do so it would become a sunna” Abu Dawud and Ibn Majah transmitted it.
Mishkat al-Masabih, 368ضَعِيفٌ (الألباني)