Ablutions (Wudu')
4/29. Chapter:
The washing of heels during ablution
وَكَانَ ابْنُ سِيرِينَ يَغْسِلُ مَوْضِعَ الْخَاتَمِ إِذَا تَوَضَّأَ.Whenever Ibn Sirin performed ablution, he used to wash the place that was under the ring.
Sahih Bukhari
حَدَّثَنَا آدَمُ بْنُ أَبِي إِيَاسٍ، قَالَ حَدَّثَنَا شُعْبَةُ، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ زِيَادٍ، قَالَ سَمِعْتُ أَبَا هُرَيْرَةَ ـ وَكَانَ يَمُرُّ بِنَا وَالنَّاسُ يَتَوَضَّئُونَ مِنَ الْمِطْهَرَةِ ـ قَالَ أَسْبِغُوا الْوُضُوءَ فَإِنَّ أَبَا الْقَاسِمِ صلى الله عليه وسلم قَالَ " وَيْلٌ لِلأَعْقَابِ مِنَ النَّارِ ".
Narrated Muhammad Ibn Ziyad: I heard Abu Huraira saying as he passed by us while the people were performing ablution from a utensil containing water, "Perform ablution perfectly and thoroughly for Abul-Qasim (the Prophet) said, 'Save your heels from the Hell-fire.' "
Reference : Sahih al-Bukhari 165In-book reference : Book 4, Hadith 31USC-MSA web (English) reference : Vol. 1, Book 4, Hadith 166