“This is concerning my question before abu ‘ Abd Allah (a.s.), about a man who with the intention to fast wakes up in the morning, then for a certain reason decides not to fast. He (the Imam) said, ‘Until midday it is his choice to fast or not to fast.’ I then asked, ‘Is he required to make Qada’ (compensatory fast) for such fast if he discontinues it?’ He (the Imam) said, ‘Yes, it is a valid deed that he intended to do and he should complete it.’ I then asked, ‘Can a man who, when the day is up, decide to fast, do so?’ He (the Imam) said, ‘Yes, it is permissible for him to do so.’”