Yahya bin Drst bin Ziyad يحيى بن درست بن زياد · The Book of Fasting

"A man came to the Messenger of Allah and said: 'O Messenger of Allah, what do you say about a man who fated for the rest of his life?' The Messenger of Allah said: 'I wish that he would never eat for the rest of his life.' He said: 'Two-thirds ( of a lifetime)?' he said: 'That is too much.' He said: 'Half?' He said: 'Shall I not tell you of that which will take away impurity from the heart?'…