Sunan Abu Dawud · Hadith 125
حَدَّثَنَا مَحْمُودُ بْنُ خَالِدٍ، حَدَّثَنَا الْوَلِيدُ، بِهَذَا الإِسْنَادِ قَالَ فَتَوَضَّأَ ثَلاَثًا ثَلاَثًا وَغَسَلَ رِجْلَيْهِ بِغَيْرِ عَدَدٍ .
Another version says:He performed each part of the ablution three times and washed his feet times without number
Sahih · Al-AlbaniSahih · Muhammad Muhyi Al-Din Abdul HamidHasan · Zubair Ali Zai