The face was red with flushing blood as he tried to stop his breath for as long as he could. The eyes bulged out, though staring at nothing. Small rivulets of perspiration shone on the forehead, and the voice coming through the foaming mouth was barely audible. He could scarcely speak when he tried to complete his sentence, and then did that through his gestures, nodding with satisfaction as if the message had been transmitted by some telepathic process.

The man, a neighbor of mine, was not faking it out. He was a highly educated professional and belonged to a very respectable family. He truly believed in what he was trying to say. Somehow -- perhaps because of my appearance -- he had a misconception that I belonged to his 'clan'. So he took very little time to begin sharing his ideas with me: 'The fragrance of flowers, the song of birds, the air, everything... but then, you know it. Yes, yes, you know it. I am Allah, you are Allah, everything is Allah....'

I realized afterward that in a very crude manner, the man was expressing (though technically incorrectly) ideas he had gathered from some Sufi...

The Qur'anic concept of Tawhid (monotheism) is that there is only one God -- Allah. All those characteristics which can only be associated with God must not be attributed to anyone else.

The Qur'an says:

Declare [O Prophet] that1 God is One2! He is the rock.3 He is neither anyone's father nor anyone's son. And none is equal to Him.[112:1-3]

Therefore, the whole world is His creation: He is above all, and there is nothing like Him.  It is the correct belief in God which enlightens the heart and solves the riddle this universe is. Every creation points out the fact that there must be a Creator and therefore reflects God:

Allah is the Light of the heavens and the earth. [24:35]

In Sufism, however, Tawhid, is expressed as 'only Absolute Reality is absolutely real'. To the Sufi, this concept of Tawhid is different from pantheism (regarded un-Islamic by almost all the Muslim scholars), for the Sufistic Tawhid is not 'everything is God': it is 'God is everything,' or, more ostensibly, 'there is nothing except God'. The result is that in Sufism, Tawhid expressed as la ilaha illallah (there is no God but Allah) is the Tawhid of the ordinary, whereas the Tawhid of the elect is la mawjuda illallah (there is nothing but Allah). This means that whatever we see does not have any significance, for it does not exist in reality. It is only relatively real. What does exist in reality is God. Ibn 'Arabi writes in his book Fasusu'l-Hikam:

Although apparently Creation is distinct from the Creator, in reality, the Creator is but Creation and Creation is but the Creator. All these are from one reality. Nay, it is but He who is the Only Reality, and it is He Who manifests Himself in all these realities.

This concept is called Wahdatu'l-Wajud (Unity of Being): the idea is that a knife and a sword, for example, are called by their respective names and are treated as distinct and separate items. But when their 'essence' steel moves wara u'l-wara ('beyond the beyond', that is beyond all forms and shapes), it is called steel. Similarly, God is considered as the Ultimate Reality, which is transcendent (beyond shape and form) but in essence immanent in Creation. In the words of Sha Muhammad Isma'il ('Abaqat, 'abaqah 20, al-isharah u'l-awwal):

For all Creation, Ma bihitta 'yun4 is only one Definite being.

Another version of this concept is Wahdatu'l-Shahud (Unity of Appearance), according to which, God is the only Reality, and everything else is illusion. This version is again the same concept expressed in a different way. According to Sha Muhammad Isma'il ('Abaqat, 'abaqah 20, al-isharahu'l-awwal):

...deep analysis will show that there is no difference except that owing to the difference in their stages and in their ways of reaching Lahut,5 they [the proponents of the two versions] have adopted varying styles to express their opinions.

Such beliefs often result in a strong tendency to regard a man's physical self as a 'form' and to consider this form as an obstruction in his going warau'l-wara (beyond the beyond) and in reaching the Ultimate Reality. Theosophical (to be more precise, existential) realization of this Reality through self-denial and self-control becomes the ultimate goal of life, whereas according to the Qur'an, the purpose of man's life is worship and servitude to God (51:56) and the purpose of religion is the purification of his soul to enable him to do just that (62:2). In Sufism, therefore, purification of the soul becomes the ultimate target of the Sufi's life rather than becoming the outcome of following the dictates of Islam. For this purification, rituals and methods other than those recommended or demanded by Islam are often prescribed with such authority6 and adhered to with such pertinacity that they virtually amount to innovation in religion. That which is a means to an end becomes the end in itself: man's humility, which in Islam leads to servitude, becomes a source of his pride in Sufism; servitude, which makes him a humble servant of his Master, makes him the Master.

According to Sufism, perfect awareness of the Absolute Reality results in the Sufi's being absolutely unaware of Creation and of his own self; to be more precise, it results in his being aware of the fact that in reality there is no existence of Creation and even of his own self. This concept often leads to great imbalance; in negating his ego, the Sufi ends up worshipping it; in negating Creation, he negates life itself.

Absolute negation of the self is impracticable, absolute negation of Creation impractical. No Man born of a woman can conceive nothingness for himself unless he is deranged enough not to perceive anything at all. Life is not insignificant. Nor is consciousness. And every one of us knows this. Life still brings laughter, death still summons tears. Intellect is still honored, lack of consciousness is still regarded as insanity. A man thinks and therefore is. When he thinks, he knows -- consciously or otherwise -- that it is 'he' who is thinking. Therefore, if he thinks or believes that he does not exist -- that only God exists --, then he will usually end up thinking or believing that it is 'he' who is actually God. But God he cannot be. For the best of men -- the messengers of God --, even in their greatness, always remained in want of their Lord's mercy for the most minor of their needs:

Allahumma inni lima anzalta ilayya min khayrin faqir

Lord! verily I am needy for anything you may bestow upon me out of good. [A prayer of Moses (sws); see the Qur'an  28:24]  Allahumma inni 'abduka, ibn 'bdika, ibn amatika, nasiyati biyadik....

Lord! verily I am your slave, the son of your bondman, the son of your bondwoman, my forelock is in your hands. [that is I am completely in your power]... [A bedtime prayer of the Prophet ﷺ].

Even a messenger of God is a servant of his Master. To him, God is the Master whom he loves with all his heart and all his mind and all his soul. To the Sufi, however, God is the beloved whose love leads him to realize the Ultimate Reality -- and thus makes him the Master (though the Sufi will sometimes deny this. However, as long as 'he' believes -- consciously or otherwise -- that nothing expect God exists, he will usually be thinking of himself as the Deity7).

The usual result of this shift in the object is that in addition to the spiritual exercises and rituals recommended or prescribed by Islam to enable man to worship and serve God, the Sufi virtually makes many other exercises and rituals obligatory, which often leave him with very little energy and motivation to do God's bidding where it is actually required. And since the Sufi has a philosophical foundation for this shift from the balance required by Islam, he usually ends up being a slave of his own desires.

Vis--vis the society as a whole, the object of an individual's life as envisaged by Sufism is impractical as absurd, as the realization of the object by all would mean negation of Creation by all and therefore negation of society, whereas realization of the object of a man's life as envisaged by Islam would result in the creation of a truly harmonious society. Worshipping and serving God entail responsibility towards society. One's affiliation with society is not negated as such in Islam as a goal for achieving self-purification, just as none of the blessings of God is negated for this purpose, howsoever trivial it may appear to be.

Only when such negation becomes necessary for preventing a greater injustice to the society or to one's own self does Islam allow -- and in some cases demand -- that an individual deny the privileges he has and negates his affiliation with his society.

In Sufism, however, there seems to be a strong tendency to regard asceticism as highly desirable per se. If nothing else, there is at least an abnormal emphasis on the negation of worldly life:

Ibn 'Ata Allah writes:

The source of every disobedience, indifference, and passion is self-satisfaction. The source of every obedience, vigilance, and virtue is dissatisfaction with one's self. (Tr. Cryil Glasse, The Concise Encyclopedia of Islam, second edition, London: Stacey International, 1991, p. 378).

Al Ghazali says in a al-Munqidh mina'l-Dalal:

Then I turned my attention to the Way of the Sufis. I knew that it could not be traversed to the end without both doctrine and practice and that the gist of the doctrine lies in overcoming the appetites of the flesh and getting rid of its evil dispositions and vile qualities, so that the heart may be cleared of all but God...

When I considered the intention of my teaching, I perceived that instead of doing it for God's sake alone I had no motive but the desire for glory and reputation. I realized that I stood on the edge of a precipice and would fall into Hellfire unless I set about to mend my ways... Conscious of my helplessness and having surrendered my will entirely, I took refuge with God as a man in sore trouble who has no resources left. God answered my prayer and made it easy for me to turn my back on reputation and wealth and wife and children and friends. (Tr. Cyril Glasse, The Concise Encyclopedia of Islam, second edition, London: Stacey International, 1991. p. 379)

Is this abnormal inclination towards asceticism deliberate? Is it obligatory or merely desirable? -- these questions may be debatable. However, one thing is certain. As far as the concept of perfect awareness of the Absolute Reality is concerned, it inevitably leads to the conceptual negation of Creation and therefore of society.

Perhaps because of the impracticability and impracticality of their ideas, the Sufis have usually regarded it desirable per se not to reveal their inner thoughts about Tawhid (and when they do reveal them, the style they use makes their language unintelligible to most people), whereas the Prophet ﷺ was told to communicate his message clearly as part of his mission (the Qur'an 5:67):

Know therefore that the ultimate of all disciples of Mystic intuition is this Tawhid, and the secrets of this discipline and cannot be written in any book because, according to a saying of 'Arifin [those who have achieved awareness], exposing the secrets of Divinity amounts to infidelity. [al-Ghazali, Ihya 'Ulumi'l-Din, Vol. 4. p. 641]

1. That has been used here as a pronoun, not as a conjunction.
2. That is unique or single in kind.
3. That is the rock which is the shelter against the enemy and is the savior (See Psalms 18:2 & 3 -- the Lord is my rock ...)
4. From which other things are, for example, a knife and a sword are from steel.
5. That is God.
6. Sufis claim direct knowledge for themselves through the same Divine source which was the basis of Divine Guidance given to the messengers of God and His Prophets (For example see Sha Muhammad Isma'il, 'Abaqat, 'Abaqah 11, al-isharahtu'l-ijmaliyyah ila maratib kamali'l-nafs). Although they believe that no further directives are given to them after the Prophet ﷺ as far as the content of religion is concerned, yet the fact that they present their 'prescriptions' for the 'application' of the principles of the Qur'an and the Sunnah on the basis of their 'direct knowledge' and therefore with the same degree of authority that religion itself has is a sufficient cause for concern over innovation in religion.
7. Perhaps that is why the walls of the tombs of the Sufi saints echo with claims as Ana al-Haq (I am God -- claimed by Hallaj) and Subhani, ma a'zama sha'ni! (I am pure! what an exalted status is mine! -- claimed by Bayazid) whenever some 'Arif in his ecstasy is unable to contain his awareness. One cannot, therefore, blame the simple followers of the Sufis as our friend with bulging eyes for thinking themselves to be God.