Fasting during Ramadan is one of the pillars of Islam. It is an obligation made by Allah and anyone who does not believe in its obligation is regarded as a disbeliever because he denies the Command of Allah and His Messenger and goes against the consensus of Muslims. Almighty Allah Says (what means): “O you who have believed, decreed upon you is fasting as it was decreed upon those before you that you may become righteous.”[Quran 2:183]
And (what means): “The month of Ramadan [is that] in which was revealed the Qur'an, a guidance for the people and clear proofs of guidance and criterion. So whoever sights [the new moon of] the month, let him fast it; and whoever is ill or on a journey - then an equal number of other days. Allah intends for you ease and does not intend for you hardship and [wants] for you to complete the period and to glorify Allah for that [to] which He has guided you; and perhaps you will be grateful.” [Quran 2: 185]
We should start fasting the month of Ramadan on seeing the crescent of the month of Ramadan. We must not precede Ramadan by fasting a day or two before it as the Prophet was reported to have ordered his Companions, may Allah be pleased with them, not to fast on such days unless it is a day in which the person usually fasts like the optional fasting of Mondays and Thursdays, then if the day before Ramadan happens to be a Monday or a Thursday, he is allowed to fast on such days. One is also allowed to fast on these days if he has to make up missed days in the previous month of Ramadan. Also, we should not fast the day of doubt (the thirtieth day of Sha’baan) if the sky is overcast (and we cannot see it). ‘Abdullaah ibn ‘Umar, may Allah be pleased with him, narrated that Allah's Messenger mentioned Ramadan and said: "Do not fast unless you see the crescent (of Ramadan), and do not give up fasting (at the end of the month) till you see the crescent (of Shawwaal), but if the sky is overcast (and you cannot see it), then count Sha’baan as thirty days.” [Al-Bukhari and Muslim]
Fasting is obligatory upon every sane healthy Muslim, who is not traveling at that time, whether man or woman unless she is in menstruation period or having post-childbirth bleeding. Fasting is not obligatory upon a non-Muslim and if he embraces Islam during the month of Ramadan, he is not obliged to make up the previous days of the month. As to the day on which he converts, he should fast till the end of the day with other people and is not obliged to make up this day. Fasting is not due upon minors but if they can tolerate fasting, they should fast to get use to its hardships. The companions of the Prophet used to encourage their children to observe fasting and when they wept out of hunger and thirst, they would give them toys to play with until sunset.
The young boy becomes an adult by three features:
1. To reach the age of fifteen.
2. The growth of the pubic hair.
3. Discharging sperm during a ‘wet dream’ or by any other method.
In addition to these conditions, which are applied to the boy, the girl becomes an adult when she experiences menstruation. Fasting becomes obligatory by meeting any of the previous conditions.
As to the insane and feeble-minded person, fasting is not obligatory and s/he is not obliged to make up any days or to pay ransom, nor s/he is required to observe purification or prayer because of his/her inability to understand what they are doing. Fasting is not obligatory upon those who are totally unable to fast like the elderly and chronically ill people but they are obliged to feed one poor person a day (for every day of fasting that they do not observe), a quarter of Saa’ (approximately 750 gm) for every day. It is better to provide some fatty ingredients and shortening with barley. If the person is not chronically ill and can tolerate fasting and no harm results, then he must fast. If he can fast but with difficulty and there is some harm, fasting is disliked. If some harm is the consequence of fasting, it is prohibited to observe fasting in such a case. On recovering, he should make up all missed days, but if he died, nothing is required. As for the pregnant and breast-feeding women, if they fear for themselves or for the baby, they are allowed to break their fast and must make up the missed days afterwards.
As for the traveler, if he intends his traveling only as a concession for him to break his fast, fasting is obligatory. However, if he travels not to enjoy the concession, fasting is optional i.e. he is allowed to break his fast and to make up the days he missed and he is also allowed to observe fasting. If fasting and breaking fast are equal to him, observing fast is better than breaking the fast because it was the tradition of the Prophet . If fasting will result in hardships because of traveling, then fasting is disliked according to Muslim scholars, may Allah have merc upon them. If traveling results in grave hardships, fasting is held prohibited. When the Messenger left for Makkah during the year of the Conquest (of Makkah)- in Ramadan, he was told that the people were experiencing hardship fasting while traveling. He then called for a cup of water, which he elevated so that the people could see it, and then drank it. Afterwards, he was told that some people had continued to fast, and he said: “Those are disobedient ones, those are disobedient ones.” [Muslim] This ruling is applied whether he travels for a need or it is continuous travel during the whole year like taxi drivers who go out of their cities.
Fasting is not obligatory on women during menses and post-childbirth bleeding and isn’t accepted from them except after purification. They must make up missed days.