The primary significance of saum is abstaining in an absolute sense (al-imsaku ani-l fi'l), and includes abstaining from eating or speaking or moving about; thus a horse that abstains from moving about, or from fodder, is said to be sa'im, and wind is said to be saum when it abates, and the day when it reaches the mid point. On two occasions in the Koran (9:112 and 66:5), those who fast are called sa'ih (from saha meaning he travelled) or spiritual wayfarers. In the sense of abstaining from speech, the word is used in the Koran in an early Meccan revelation: "Say, I have vowed a fast to the Beneficent God, so I shall not speak to any man today" (19:26). This however appears to be a fast (siyam) to keep silent and not to talk with any person; a similar fast of silence is spoken of in the case of Zacharias: "Thy sign is that thou shouldst not speak to men for three days except by signs, and remember thy Lord much and glorify Him in the evening and the morning" (3:4). It indicates that the object of the fast of silence was the remembrance of God.
In the technical language of the Islamic law, saum and siyam signify fasting or abstaining from food and drink from dawn till sunset. The word saum occurs 13 times in the Koran. Fasting commences with the new moon of Ramzan and ends on the appearance of the new moon of Shawal. What has been said hitherto relates only to the external side of the fast, but its essence is its moral and spiritual value. While laying down a practice, the Prophet primarily considered the value and spirit of the action and not the form of the action. The Prophet said, "Whoever does not give up lying and acting falsely, Go does not stand in need of his giving up food and drink" (Bukhari, 30:8).
Abstinence involves not only keeping the belly without food and drink, but needs guarding the eyes from lustful looks and the ear from listening to evil speech and the tongue from vain or foul words, and the body from following after worldly things. One who acts in this manner is truly keeping his fast, for the Prophet said to a certain person, "When you fast, let your ear fast and your eye and your tongue and your hand and every limb;" and he also said, "Many a one has no good of his fasting except hunger and thirst" (Kash al-Mahjub by Hujwiri, tr. Nicholson, London, 1967, p. 321). "To abstain only from food and drinks is child's play. One must abstain from idle pleasures and unlawful acts, not from eating lawful food. I marvel at those who say that they are keeping a voluntary fast and yet fail to perform an obligatory duty. Not to commit sin is obligatory, whereas continual fasting is an apostolic custom. When a man is divinely protected from sin all his circumstances are a fast" (Ibid., p. 322). "The spirit of man gains strength when he tries to obey God's orders and to restrain himself from those things that are prohibited by God. Unless he does so, physical abstentions alone cannot be counted as fasting" (Encyclopaedia of Islamic Spirituality, Lahore, 2000, 1:118).
The prime means for taming the nafs are the three elements in Sufi conduct, i.e., little food (qillat at-ta'am), little sleep (qillat al-manam) and little talk (qillat al-kalam). These important performances are mainly exhorted in the Ismaili tariqah in daily routine of life throughout the year.