"The substance of Sufism is the Truth and the meaning of Sufism is the selfless experiencing and actualization of the Truth. The practice of Sufism is the intention to go towards the Truth, by means of love and devotion. This is called the tariqat, the spiritual path or way towards God. The sufi is one who is a lover of Truth, who by means of love and devotion moves towards the Truth, towards the perfection which all are truly seeking. As necessitated by love's jealousy, the sufi is taken away from all except the Truth."

What is Sufism? - The Nimatullahi Sufi Order

"Drawing on their own experiences, the Sufi masters describe the inner workings of the path of love. They tell how longing for God burns away our impurities. They remind us that by remembering God we come closer to our eternal essence and that in our moments of utmost despair the Beloved reveals Himself: He who had seemed so distant is discovered 'closer to you than yourself to yourself.' They share their glimpses of the essential oneness of all life and, with simplicity, directness, and humor, describe the paradoxical nature of this mystical journey."

The ninth-century ecstatic Bâyezîd Bistâmî, who left no writings, is known for his utterances made in a state of divine intoxication, like 'Glory be to me. How great is my majesty!' Al-Junayd, who taught in Baghdad in the ninth century, advocated a path of sobriety and the integration of mysticism into ordinary life. At the same time in Baghdad the prince of lovers, al-Hallâj, spoke of the essential unity of lover and Beloved and was put to death for exclaiming the mystical truth 'anâ'l-Haqq' ( I am the Absolute Truth). In the eleventh century in Nishapur the great master Abû Sa'îd ibn Abî-l-Khayr stressed the need to abandon the ego, or nafs, in order to realize the Pure Self.

TRAVELLING THE PATH OF LOVE - Edited by Llewellyn Vaughan-Lee

While all Muslims believe that they are on the pathway to God and will become close to God in Paradise — after death and after the "Final Judgment" — Sufis also believe that it is possible to draw closer to God and to more fully embrace the Divine Presence in this life. The chief aim of all Sufis is to seek the pleasing of God by working to restore within themselves the primordial state of fitra, described in the Qur'an and similar to the concept of Buddha nature. In this state nothing one does defies God, and all is undertaken by the single motivation of love of God. A secondary consequence of this is that the seeker may be led to abandon all notions of dualism or multiplicity, including a conception of an individual self, and to realize the Divine Unity.

Thus Sufism has been characterized as the science of the states of the lower self (the ego), and the way of purifying this lower self of its reprehensible traits, while adorning it instead with what is praiseworthy, whether or not this process of cleansing and purifying the heart is in time rewarded by esoteric knowledge of God. This can be conceived in terms of two basic types of law (fiqh), an outer law concerned with actions, and an inner law concerned with the human heart. The outer law consists of rules pertaining to worship, transactions, marriage, judicial rulings, and criminal law — what is often referred to, a bit too broadly, as shariah. The inner law of Sufism consists of rules about repentance from sin, the purging of contemptible qualities and evil traits of character, and adornment with virtues and good character.

To enter the way of Sufism, the seeker begins by finding a teacher, as the connection to the teacher is considered necessary for the growth of the pupil. The teacher, to be genuine, must have received the authorization to teach (ijazah) of another Master of the Way, in an unbroken succession (silsilah) leading back to Sufism's origin with the Prophet Muhammad. It is the transmission of the divine light from the teacher's heart to the heart of the student, rather than of worldly knowledge transmitted from mouth to ear, that allows the adept to progress. In addition, the genuine teacher will be utterly strict in his adherence to the Divine Law.

Scholars and adherents of Sufism are unanimous in agreeing that Sufism cannot be learned through books. To reach the highest levels of success in Sufism typically requires that the disciple live with and serve the teacher for many, many years. For instance, Baha-ud-Din Naqshband Bukhari, considered founder of the Naqshbandi Order, served his first teacher, Sayyid Muhammad Baba As-Samasi, for 20 years, until as-Samasi died. He subsequently served several other teachers for lengthy periods of time. The extreme arduousness of his spiritual preparation is illustrated by his service, as directed by his teacher, to the weak and needy members of his community in a state of complete humility and tolerance for many years. When he believed this mission to be concluded, his teacher next directed him to care for animals, curing their sicknesses, cleaning their wounds, and assisting them in finding provision. After many years of this he was next instructed to spend many years in the care of dogs in a state of humility, and to ask them for support.

As a further example, the prospective adherent of the Mevlevi Order would have been ordered to serve in the kitchens of a hospice for the poor for 1,001 days prior to being accepted for spiritual instruction, and a further 1,001 days in solitary retreat as a precondition of completing that instruction.

Some teachers, especially when addressing more general audiences, or mixed groups of Muslims and non-Muslims, make extensive use of parable, allegory, and metaphor. Although approaches to teaching vary among different Sufi orders, Sufism as a whole is primarily concerned with direct personal experience, and as such has sometimes been compared to other, non-Islamic forms of mysticism (e.g., as in the books of Seyyed Hossein Nasr).

Sufism, which is a general term for Muslim mysticism, sprang up largely in reaction against the worldliness which infected Islam when its leaders became the powerful and wealthy rulers of multitudes of people and were influenced by foreign cultures. Harun al-Rashid, eating off gold and silver, toying with a harem of scented beauties, surrounded by an impenetrable retinue of officials, eunuchs and slaves, was a far cry from the stern simplicity of an Umar, who lived in the modest house, wore patched clothes and could be approached by any of his followers.

The typical early Sufi lived in a cell of in a mosque and taught a small band of disciples. The extent to which Sufism was influenced by Buddhist and Hindu mysticism, and by the example Christian hermits and monks, is disputed, but self-discipline and concentration on God quickly led to the belief that by quelling the self and through loving ardour for God it was possible to maintain a union with the divine in which the human self melted away.

Source: http://en.wikipedia.org/wiki/Sufism