O Bilāl, tell me of the most rewarding deed you have done in Islam

The Prophet (ﷺ) saw in a dream that he was in Paradise. He said to Bilāl ibn Rabāh: Tell me about the most rewarding voluntary deed you have done in Islam, for I heard the soft sound of your sandals ahead of me in Paradise. Bilāl said: The deed I consider most rewarding is that whenever I break my ablution, I perform ablution—at any hour of the day or night— and I would pray with that ablution as many voluntary prayers as ordained for me to pray.