Sunan Ibn Majah, Book 1, Hadith 549 (In-Book) ⓘ
It was narrated that Anas bin Malik said: "The Messenger of Allah used to perform ablution for every prayer, and we used to perform all of the prayers with one ablution."
حَدَّثَنَا سُوَيْدُ بْنُ سَعِيدٍ، حَدَّثَنَا شَرِيكٌ، عَنْ عَمْرِو بْنِ عَامِرٍ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ كَانَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ يَتَوَضَّأُ لِكُلِّ صَلاَةٍ وَكُنَّا نَحْنُ نُصَلِّي الصَّلَوَاتِ كُلَّهَا بِوُضُوءٍ وَاحِدٍ .
also referenced under: Hadith 509 (Reference) & Volume 1, Book 1, Hadith 509 (DarusSalam)