Narrated Mujahid from `Abdullah bin `Amr: The Prophet said (to `Abdullah), Fast three days a month. `Abdullah said, (to the Prophet) I am able to fast more than that. They kept on arguing on this matter till the Prophet said, Fast on alternate days, and recite the whole Qur'an once a month. `Abdullah said, I can recite more (in a month), and the argument went on till the Prophet said, Recite the Qur'an once each three days. (i.e. you must not recite the whole Qur'an in less than three days).