Sahih al-Bukhari 1149
Book 19: Prayer at Night (Tahajjud) · Narrated by Abu Huraira
Arabic
حَدَّثَنَا إِسْحَاقُ بْنُ نَصْرٍ، حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ أَبِي حَيَّانَ، عَنْ أَبِي زُرْعَةَ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ لِبِلاَلٍ عِنْدَ صَلاَةِ الْفَجْرِ " يَا بِلاَلُ حَدِّثْنِي بِأَرْجَى عَمَلٍ عَمِلْتَهُ فِي الإِسْلاَمِ، فَإِنِّي سَمِعْتُ دَفَّ نَعْلَيْكَ بَيْنَ يَدَىَّ فِي الْجَنَّةِ ". قَالَ مَا عَمِلْتُ عَمَلاً أَرْجَى عِنْدِي أَنِّي لَمْ أَتَطَهَّرْ طُهُورًا فِي سَاعَةِ لَيْلٍ أَوْ نَهَارٍ إِلاَّ صَلَّيْتُ بِذَلِكَ الطُّهُورِ مَا كُتِبَ لِي أَنْ أُصَلِّيَ. قَالَ أَبُو عَبْدِ اللَّهِ دَفَّ نَعْلَيْكَ يَعْنِي تَحْرِيكَ.
English translation
Narrated Abu Huraira:At the time of the Fajr prayer the Prophet (ﷺ) asked Bilal, "Tell me of the best deed you did after embracing Islam, for I heard your footsteps in front of me in Paradise." Bilal replied, "I did not do anything worth mentioning except that whenever I performed ablution during the day or night, I prayed after that ablution as much as was written for me
Reference: Sahih al-Bukhari 1149, Book of Prayer at Night (Tahajjud). English translation by Dr. Muhammad Muhsin Khan.