Chapter 81: To make the Heart Tender (Ar-Riqaq)
Narrated Masruq: I asked 'Aisha "What deed was the most beloved to the Prophet?" She said, "The regular constant
one." I said, "At what time did he use to get up at night (for the Tahajjud night prayer)?' She said, "He
used to get up on hearing (the crowing of) the cock (the last third of the night).
Sahih al-Bukhari 6461