Sahih Bukhari

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