Fasting is an ancient and universal practice. The Romans, the Babylonians, the Cynic, Stoic, Pythagorean and Neo-Platonist philosophers commended fasting. The followers of Hinduism, Jainism, Confucianism, and Zoroastrianism practice it. The Jews observe an annual fasting on the day of atonement in commemoration of the descent of Moses from Sinai after spending forty days of fasting in order to be able to receive revelation. Jesus observed fasting for forty days in the desert and commanded his followers to fast. In brief, the practice of fasting has been common in one form or the other in all human societies.
Before the advent of Islam, fasting was resorted to by way of repentance or penance, or as a mark of mourning, or to celebrate some particular occasion, or to ward off an apprehended danger, or to control a prevailing epidemic, or to gratify and please a deity or to put pressure to achieve a certain desire end. The form of fasting also differed. For example, Jews ate only once in twenty-four hours. Among Hindus, the restriction applies only to cereals whereas eating of fruits or taking of liquids during fasting is not prohibited. In fact, in ancient faiths and creeds, the objects of fasting were very limited, the intention generally being self-mortification, asceticism, or the satisfaction of some of some superstitious urge.
Originally, in Arabic the word 'as-Sawm' (Sawm) meant 'al-Imsak', that is, to abstain totally from any act including eating, drinking, walking, speaking, etc. Thus, the Arabs used to refer to a horse refusing to run or to be fed, as 'Saum', that is, fasting. As is clear, the word 'Sawm' is ancient and was used in a different context by the Arabs before Islam. Then, however it did not have the specific meaning given to it by Islam as a term denoting a certain religious obligation. As an Islamic term, it means to refrain intentionally from what breaks fasting.
To a Muslim, Ramadan fasting is not just refraining from eating and drinking but carries the added significance of worship, psychological comfort, morality and legislation. It is neither the irrational motionless 'Imsak' of pre-Islamic Arabs nor the mere abstaining from eating and drinking, but is, in fact, the building of one's character, control over desires, and an inspiration towards social and scientific creativity.
God has commanded this sanctified duty and enjoined it on the Muslims, as He had enjoined it on the believing nations before. He assigned the blessed month, the month of Ramadan, for every adult and healthy Muslim as a period of fasting. This sacred ordinance was prescribed by God, for all believers and revealed in the preceding month of Shaaban, nearly a year and a half after the Hijra (the Prophet's auspicious migration from Makkah to Medina [in 622 BC] which marks the start of the Islamic calendar).
Gradually, God revealed numerous other verses about the month of Ramadan and the rules of fasting. In light of these divine injunctions, Holy Prophet Muhammad (S.A.W.) expounded the merits of fasting, its significance, regulations, effects, benefits and great reward. Hence, fasting is one of the pillars of Islam and a religious duty for all those who believe in monotheism, and consequently, whoever denies it is an unbeliever.
It is an apparent sign of obedience, submission and servitude to God, the Exalted. By fasting, a Muslim expresses his submission to Allah's command, his response to His will, and control over his own desires and wishes at the God's behest.
In the holy month of Ramadan, a Muslim's abstaining from food, drink, sexual intercourse, etc., during the prescribed hours is the very manifestation of obedience to the Creator's will. This self-deprivation represents a state of self-control and of overcoming carnal pleasure, desire, and enjoyment, for the blissful love of God, His proximity, and the eagerness to desires. It is a triumph of pristine love over one's pleasures for the eternal ones promised by God, the Almighty. This response to the Divine commandments represents and incarnates true servitude and is a brilliant display of spirit, intellect and decisive willpower.
By fasting, a person keeps himself from the pleasures of life, with no preventive or hindering factor, except that of obeying God and showing genuine devotion to His commands. Traditions (ahadith) succinctly explain this fact: "A fasting person is in a state of worship, even when (asleep) in bed, except when he backbites another Muslim." (Al-Kafi, al- Kulayni, "The Book of Fasting" 3rd Edition, vol.4, p.190) "... Every breath you take is (has the reward of) Tasbih (praise to Allah) and your sleep is worship..." (Uyun al-Akhbar al-Rida - the Prophet's sermon).
In a moving speech, the Prophet of Allah described the believing soul that fasts for love of Allah out of truthfulness and sincerity, and thus the whole day becomes an alter of worship, and each and every activity of the fasting body, provided it abstains from loathsome acts, is nothing but worship embodied.
Holy Prophet Muhammad (S.A.W.) described the sleep of a fasting Muslim, even the very breathing, as acts of worship, because they emanate from a body regarded as being in a state of continual worship through abstaining from tasting delicious and lawful things, solely out of obedience to the Creator. He Himself extols fasting and attributes as a special blessing for mankind as is clear from a 'Hadith-e-Qudsi': Holy Prophet Muhammad (S.A.W.) said: "God, the Exalted says: 'Fasting is (exclusively) for Me and I will reward it." Ali ibn Musa al-Rida (A.S.), the Eighth Imam quoted his ancestor Holy Prophet Muhammad (S.A.W.) on the chain of authority of his noble forefathers: "O people, any body who in this month (Ramadan) cultivates good manners, will walk over the 'Sira' (Paradise's bridge) on the Day when feet will tend to slip...." ('Uyun alAkhbar, al-Rida - Prophet's sermon).
A fasting person is in a state of worship, even when (asleep) in bed, except when he backbites another Muslim.
The practices of Islamic fasting are designed to divert human mind towards righteousness through a process of self-denials. Fasting constitutes a process of self-purification, self-righteousness, and spiritual development of one self.
Fasting in Islam is not prescribed to cause undue hardship. The Divine principle, as specified in the Holy Quran: (On no soul does God place a burden greater than it can bear...) (2:286).
Accordingly, although there can be no laxity in so far as the obligation of fasting is concerned, there are facilities provided for one who may be sick or on a journey. The Holy Quran says: (...But if any one is ill, or on a journey, the prescribed period (of fasting should be made up) by days later. God intends every facility for you; He does not want to put you to difficulties ...) (2:185).