Sunan an-Nasa'i, Book 1, Hadith 132 (In-Book) ⓘ

It was narrated from 'Amr bin 'Amir that Anas mentioned: "The Messenger of Allah was brought a small vessel (of water) and he performed Wudu'." I said: "Did the Messenger of Allah perform Wudu' for every prayer?" He said: "Yes." He said: "What about you?" He said: "We used to pray all the prayers so long as we did not commit Hadath." He said: "And we used to pray all the prayers with (one) Wudu'."

أَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ الأَعْلَى، قَالَ حَدَّثَنَا خَالِدٌ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ عَمْرِو بْنِ عَامِرٍ، عَنْ أَنَسٍ، أَنَّهُ ذَكَرَ أَنَّ النَّبِيَّ صلى الله عليه وسلم أُتِيَ بِإِنَاءٍ صَغِيرٍ فَتَوَضَّأَ ‏.‏ قُلْتُ أَكَانَ النَّبِيُّ صلى الله عليه وسلم يَتَوَضَّأُ لِكُلِّ صَلاَةٍ قَالَ نَعَمْ ‏.‏ قَالَ فَأَنْتُمْ قَالَ كُنَّا نُصَلِّي الصَّلَوَاتِ مَا لَمْ نُحْدِثْ قَالَ وَقَدْ كُنَّا نُصَلِّي الصَّلَوَاتِ بِوُضُوءٍ ‏.‏