(9) باب وُجُوبِ غَسْلِ الرِّجْلَيْنِ بِكَمَالِهِمَا
Abu Huraira reported:
Allah's Apostle (ﷺ) saw a man who did not wash his heel and he remarked: Woe to the heels because of hell-fire.
Reference: Sahih Muslim 242a
In-book reference: Book 2, Hadith 40
USC-MSA web (English) reference(deprecated numbering scheme): Book 2, Hadith 471