"The Messenger of Allah saw some people performing ablution, and their heels were dry. He said: 'Woe to the heels because of Hell-fire, perform ablution properly!'" (Using translation from Ibn Mājah 450)
رَأَى رَسُولُ اللهِ ﷺ قَوْمًا يَتَوَضَّئُونَ وَأَعْقَابُهُمْ تَلُوحُ فَقَالَ وَيْلٌ لِلْأَعْقَابِ مِنَ النَّارِ أَسْبِغُواالْوُضُوءَ