Sahih Muslim 241a
'Abdullah b. 'Amr reported: 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.
وَحَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا جَرِيرٌ، ح وَحَدَّثَنَا إِسْحَاقُ، أَخْبَرَنَا جَرِيرٌ، عَنْ مَنْصُورٍ، عَنْ هِلاَلِ بْنِ يِسَافٍ، عَنْ أَبِي يَحْيَى، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو، قَالَ رَجَعْنَا مَعَ رَسُولِ اللَّهِ ﷺ مِنْ مَكَّةَ إِلَى الْمَدِينَةِ حَتَّى إِذَا كُنَّا بِمَاءٍ بِالطَّرِيقِ تَعَجَّلَ قَوْمٌ عِنْدَ الْعَصْرِ فَتَوَضَّئُوا وَهُمْ عِجَالٌ فَانْتَهَيْنَا إِلَيْهِمْ وَأَعْقَابُهُمْ تَلُوحُ لَمْ يَمَسَّهَا الْمَاءُ فَقَالَ رَسُولُ اللَّهِ ﷺ " وَيْلٌ لِلأَعْقَابِ مِنَ النَّارِ أَسْبِغُوا الْوُضُوءَ " .