"We were sitting with 'Abdullah bin 'Abbas and he said: 'By Allah, the Messenger of Allah ﷺ did not say specifically anything for us above the people, except for three things: He commanded us to do Wudu' properly, [2] not to consume charity, and not to mate donkeys with horses.'" [1] Isbagh Al-Wudu' [2] An Nusbig Al-Wudu'  

وَاللَّهِ مَا خَصَّنَا رَسُولُ اللَّهِ ﷺ بِشَىْءٍ دُونَ النَّاسِ إِلاَّ بِثَلاَثَةِ أَشْيَاءَ فَإِنَّهُ أَمَرَنَا أَنْ نُسْبِغَ الْوُضُوءَ وَلاَ نَأْكُلَ الصَّدَقَةَ وَلاَ نُنْزِيَ الْحُمُرَ عَلَى الْخَيْلِ  

"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."  

قَالَ رَسُولُ اللَّهِ ﷺ أَسْبِغُوا الْوُضُوءَ