1- Islam. An original kafir (non-Muslim) is not required to fast.

However, an apostate is requested to fast, by saying to him: "Come back to Islam and fast".

His fast is not accepted while he is an apostate.

Though, when an apostate returns to Islam he should make up what he missed during the period of apostasy unlike an original kafir who is not obliged to make up for missed fasting during the time he was kafir because fasting was not obligatory for him at the time.

Amr ibn Al-Aas (G. p. H) narrated that the Prophet (P. B. U. H) said:

"Didn't you know that Islam demolishes what was prior to it".

[Muslim, Vol. 1, The Book of Faith, Chapter 54/192].

2- Sanity (mental balance).

Fasting is not obligatory for an insane, unconscious, or drunk person whether or not he is responsible for his insanity, unconsciousness, or drunkenness.

Alt ibn Abu Taleb (G. p. H) narrated that the Prophet (P. B. U. H) said:

"The pen has been lifted (Lifting the pen means that the person is not accountable (for his actions).

It does not mean the literal lining of the pen) from three: The sleeper until he awakens, the child until his first wet dream, and the insane (person) until he can reason"

[Abu Dawood, Vol. 4, The Book of Penalties, Chapter 16/4403].

One should make up for missed fasting days if he is responsible for his insanity or drunkenness.

In the case of unconsciousness, one must make up for missed fasting days even if he is not responsible for his unconsciousness for Allah (G. B. H) says:

{But if any of you is ill or on a journey, the prescribed number (should be made up) from days later,} [Al-Baqara: 184] and unconsciousness is an illness unlike insanity which is a deficiency.

Hence, whoever loses his sanity as a result of illness, taking a drug out of necessity, or any other excuse should make up for the missed days of fasting. (pa:292 )

3- Puberty. Fasting is not obligatory for a discriminating child, though his fast is acceptable.

By analogy with prayer, a seven year old should be encouraged to fast if

he can bear it and a ten year old should be struck for leaving it provided he is physically able).

4- Ability. This means the ability to fast without hardship.