From The Shadhili Tariqa
Sufism is a knowledge through which one knows the states of the human soul, praiseworthy or blameworthy, how to purify it from the blameworthy and ennoble it by acquiring the praiseworthy, and to journey and proceed to Allah Most High, fleeing unto Him. Its fruits are the heart’s development, knowledge of God through direct experience and ecstasy, salvation in the next world, triumph through gaining Allah’s pleasure, the attainment of eternal happiness, and illuminating and purifying the heart so that noble matters disclose themselves, extraordinary states are revealed, and one perceives what the insight of others is blind to
— Muhammad Amin Kurdi
The way of Sufism is based on five principles: having godfearingness privately and publicly, living according to the sunna in word and deed, indifference to whether others accept or reject one, satisfaction with Allah Most High in dearth and plenty, and returning to Allah in happiness or affliction. The principles of treating the illnesses of the should are also five: lightening the stomach by diminishing one’s food and drink, taking refuge in Allah Most High from the unforeseen when it befalls, shunning situations involving what one fears to fall victim to, continually asking for Allah’s forgiveness and His blessings upon the Prophet (Allah bless him and give him peace) night and day with full presence of mind, and keeping the company of him who guides one to Allah
— Imam Nawawi
Aspects of Sufism, defined, delineated, and explained, amount to nearly two thousand, all of them reducible to sincerity in turning to Allah Most High, something of which they are only facets, and Allah knows best. The necessary condition of sincerity of approach is that it be what the Truth Most High accepts, and by the means He accepts. Now something lacking its necessary condition cannot exists, “And He does not accept unbelief for His servants” (Koran 39:7), so one must realize true faith (iman), “and if you show gratitude, He will accept it of you” (Koran 39:7), which entails applying Islam. So there is no Sufism except through comprehension of Sacred Law, for the outward rules of Allah Most High are not known save through it, and there is no comprehension of Sacred Law without Sufism, for works are nothing without sincerity of approach.
— Ahmad Zarruq
PERHAPS the best description of the path of Sufism, certainly one of the most frequently cited among its scholars, is the hadith of the Prophet (Allah bless him and give him peace):
Allah Most High says:
“Whomever is hostile to a friend of Mine I declare war against. My slave approaches Me with nothing more beloved to Me than what I have made obligatory upon him, and My slave keeps drawing nearer to Me with voluntary works until I love him. And when I love him, I am his hearing with which he hears, his sight with which he sees, his hand with which he seizes, and his foot with which he walks. If he asks Me, I will surely give to him, and if he seeks refuge in Me, I will surely protect him. I do not hesitate from anything I shall do more than My hesitation to take the soul of the believer who dislikes death; for I dislike displeasing him” (Bukhari, 8.131: 6502. S).
This hadith describes the means to the change that is central to spiritual realization, in conformity with the teaching of the sheikhs of the path who define a Sufi as “a scholar of religious learning (faqih) who practiced what he knew, so Allah bequeathed him knowledge of what he did not know.” While people differ in their capacity both to learn the religion and to attain the consummate awareness of tawhid or ‘divine unity’ expressed in the above hadith, everyone who travels the Shadhili path (tariqa) must know the works needed to “practice what one knows.” If one is great in them, one will be great in spiritual attainment, and if one is weak in them, one will be weak in spiritual attainment, unable to pass from transitory experiences (ahwal) to permanent realization (tahqiq).