صحيح البخاري Sahih Bukhari كتاب الوضوء The Book of Wudu (Ablution)
بَابُ غَسْلِ الرِّجْلَيْنِ وَلاَ يَمْسَحُ عَلَى الْقَدَمَيْنِ:

(27) Chapter. Washing both feet, and it is not sufficient to pass wet hands over the feet.

1 hadith
Hadith 163
حَدَّثَنَا مُوسَى ، قَالَ : حَدَّثَنَا أَبُو عَوَانَةَ ، عَنْ أَبِي بِشْرٍ ، عَنْ يُوسُفَ بْنِ مَاهَكَ ، عَنْ عَبْدِ اللَّهِ بْنِ عَمْرٍو ، قَالَ : تَخَلَّفَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَنَّا فِي سَفْرَةٍ سَافَرْنَاهَا ، فَأَدْرَكَنَا وَقَدْ أَرْهَقْنَا الْعَصْرَ ، فَجَعَلْنَا نَتَوَضَّأُ وَنَمْسَحُ عَلَى أَرْجُلِنَا ، فَنَادَى بِأَعْلَى صَوْتِهِ : " وَيْلٌ لِلْأَعْقَابِ مِنَ النَّارِ مَرَّتَيْنِ أَوْ ثَلَاثًا " .
Narrated `Abdullah bin `Amr: The Prophet remained behind us on a journey. He joined us while we were performing ablution for the `Asr prayer which was overdue and we were just passing wet hands over our feet (not washing them thoroughly) so he addressed us in a loud voice saying twice , "Save your heels from the fire."
Hadith Reference Sahih Bukhari / The Book of Wudu (Ablution) / Hadith: 163
Hadith Grading محدثین: أحاديث صحيح البخاريّ كلّها صحيحة