ذِكْرُ الْعِلَّةِ الَّتِي مِنْ أَجْلِهَا أَمَرَ بِإِسْبَاغِ الْوُضُوءِ
We returned from Mecca to Medina with the Messenger of Allah ﷺ, and when we came to some water on the way, some of the people were in a hurry at the time of the afternoon prayer and performed ablution hurriedly; and when we reached them, their heels were dry, no water had touched them. The Prophet ﷺ said: Woe to (dry) heels, because of Hell-fire. Make your ablution thorough. (Using translation from Muslim 241a)
رَجَعْنَا مَعَ رَسُولِ اللَّهِ ﷺ مِنْ مَكَّةَ إِلَى الْمَدِينَةِ حَتَّى إِذَا كُنَّا بِبَعْضِ الطَّرِيقِ تَعَجَّلَ قَوْمٌ عِنْدَ الْعَصْرِ فَتَوَضَّؤُوا وَهُمْ عِجَالٌ قَالَ فَانْتَهَيْنَا إِلَيْهِمْ وَأَعْقَابُهُمْ تَلُوحُ لَمْ يَمَسَّهَا الْمَاءُ فَقَالَ رَسُولُ اللَّهِ ﷺ «وَيْلٌ لِلْأَعْقَابِ مِنَ النَّارِ أَسْبِغُوا الْوُضُوءَ»