Who are those who are not obligated to fast and will not be held accountable for it, and who are those who are obligated to fast and will be held accountable for it?

Fasting is not obligatory for the young child who has not reached puberty, nor for the insane. As for the Muslim, who is accountable, healthy, and a resident, fasting is obligatory for him. The sick and the traveler may break their fast and make up for it later. Whoever has an illness from which recovery is not expected, or is elderly and unable to fast, may break their fast and feed a poor person for each day. A menstruating woman and a woman in post-natal bleeding do not fast, but they must make up for the missed fasts.