Hammad bin Salama حماد بن سلمة · The Book of Fasting

"When you see the crescent then fast, and when you crescent then fast, and when you see it, stop fasting. If it is obscured from you (too cloudy), then fast thirty days."

"The Messenger of Allah used to be keen to fast on Mondays and Thursday."

"The Messenger of Allah said to me: 'Fast one day of the month and you will have the reward of what is left.' I said: 'I am able to do more than that.' He said: 'Fast two days and you will have the reward of what is left.' I said: 'I am able to do more than that.' He said: 'Fast three days and you will have the reward of what is left.' I said: 'I am able to do…