Sunan an-Nasa'i 142
سنن النسائي#142Sahihأَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا جَرِيرٌ، عَنْ مَنْصُورٍ، عَنْ هِلاَلِ بْنِ يِسَافٍ، عَنْ أَبِي يَحْيَى، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " أَسْبِغُوا الْوُضُوءَ " .
It was narrated that 'Abdullah bin 'Amr said:"The Messenger of Allah (ﷺ) said: 'Do Wudu' properly.'" [1] [1] Isbighu Al-Wudu'. And this narration supports the claim that some of them used this expression to mean "three times" for each limb, rather than "properly
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 1:143