It was narrated from Abu Nawfal bin Abi 'Aqrab, from his father, that he asked the Prophet about fasting and he said:
Fast one day of each month. He asked him for more, saying: May my father and mother be ransomed for you, I am able. He said: Fast two days of each month. He said May my father and mother be sacrificed for you, O Messenger of Allah, I am able. The Messenger of Allah said: I am able, I am able. He did not want to increase it, but when I insisted, the Messenger of Allah said: Fast three days of each month. (Sahih) The end of what the Shaikh had about fasting, all praise is due to Allah the Lord of the worlds.