Mukhtasar Bukhari

Narrated Abdullah bin Amr bin Al-As (may Allah be pleased with him): The Messenger of Allah (peace and blessings of Allah be upon him) said to him: "The prayer most beloved to Allah is the prayer of Dawud (David), and the fasting most beloved to Allah is the fasting of Dawud. He would sleep half the night, pray for one third of it, and then sleep for one sixth of it. And he would fast one day and not fast the next day."