The advent of Islam in India was followed by that of Sufism, the name given to the mystical, humanistic, speculative or rational and spiritual movement in the religion founded by the Prophet of Arabia. The suffix 'ism' suggests it to be a sect or creed, dogma or doctrine, definite and systematised; it is neither. Mysticism in Islam as in other religions, is less a doctrine than a certain mode of thinking, feeling and acting. It is an art or way to find out and attain God. The term mystical signifies a doctrine concerning the way to God in perfections derived from inner experiences, and interpretations rather than from deduction or reasoning. The earliest Sufis were a sect of ascetics and quietists as well as those whose aim was to purify and spritualise Islam from within, and give it a deeper mystical interpretation’ and infuse in it a spirit of love. Prof. Arberry defines Mysticism as a "constant and unvarying phenomena of the universal yearning of the human spirit for personal communion with God". Sufism was originally a practical system of religious beliefs and not a speculative system. It was a system of thought or action based on noble ideals of human nature, holding that man is capable of self-fulfilment and of ethical conduct. It absorbed the essence of Islamic teachings, the wisdom of the ancient Masters and the learning of the humanists. It assimilated many a divergent ingredient and presented them in a new dress. A time soon came when it broke with the formal, dogmatic theory by giving a new and fresh interpretation of the Creator and the Creation. It became Monistic rather than dualistic, believing in identity and fusion rather than separation like orthodox Islam. The theologians, jurists and traditionalists adhered to the letter of the law and detailed formulas and set rules of rituals and ceremonies which were fixed and were to be followed in daily life. There grew a new tendency of pantheistic mysticism which, according to Stobart, "developed itself chiefly in a search for metaphisica1 purity for illumination of the mind, for calmness of soul, and for subjugation of passions by the exercise of painful austerities and the adoption of ascetic life". The adherents of the system believed that the Divine nature pervaded all things and gave its very essence and being to the soul itself, which thus sought to gain a conformity to the Supreme Being, and more and more to sever itself from the things of earth, like a wearied traveller, seeking to terminate the period of exile from its original. The final object of the Sufi devotee is to attain the Light of Heaven, towards which he must press forward till perfect knowledge is reached in his Union with God, to be consummated, after death, in absorption into the Divine Being".
Islamic mysticism or the School of inner spirit, giving an inner and esoteric interpretation of the teachings of the Quran and the sayings and practices of the prophet, and challenging very often the power of the School of formal or externalist theologians, arose as a revitalising current in Islam between the 9th and 10th centuries and attained its fullest and classical form in the 12th and 13th centuries from the works of a group of intellectuals to whom the terminology of Mystics could be applied. They consisted of most educated men, emotional writers, and poets in Persia, Central Asia and throughout the East. By the time it came to India, Muslim mystic thought and philosophy, regarded as embodying the vital flexible spirit of Islam, the core of the belief whereof was the relationship of ‘I & Thou' had already been well established outside our country.