Sunan Ibn Majah, Hadith 412 ⓘ
It was narrated that 'Umar said: "I saw the Messenger of Allah during the campaign of Tabuk performing ablution, washing each part once."
حَدَّثَنَا أَبُو كُرَيْبٍ، حَدَّثَنَا رِشْدِينُ بْنُ سَعْدٍ، أَنْبَأَنَا الضَّحَّاكُ بْنُ شُرَحْبِيلَ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ أَبِيهِ، عَنْ عُمَرَ، قَالَ رَأَيْتُ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ فِي غَزْوَةِ تَبُوكَ تَوَضَّأَ وَاحِدَةً وَاحِدَةً .
also referenced under: Book 1, Hadith 446 (In-Book) & Volume 1, Book 1, Hadith 412 (DarusSalam)