Some of the posters here, probably influenced by Ibn Taimiyya and Abdul Wahab Najd have no clue of what they are writing. If you belong to Ahle Sunna Wal Jamaa' you should know that Imam Ghazali was one of the greates shcolars of Islam after the beloved Prophet's (SAW) life and he himself was a Sufi and went in to the world of tasawwuf.
Do you guys really know what tasawwuf is? The goal of a sufi is to turn away from the the temptations of this world and just concentrate of Allah SWT. How can that be wrong? Prove it!!! This is not a sect, only a way of coming close to Allah SWT and should be everyone's aim.
One of the asools of fiqh is that you can not deem something haram if you don't have prove of it. The burden of proving this is on your burden.
And some were quoting Ibn Arabi here. Hey listen, how much knowledge do you have of Islam to come and start critisizing him? Be careful of judging him because with your amount of knowledge you can't understand him. People have spent years to study his books and you come here and quote a sentence of him and take it litterally. Be careful!
And I also read someone distincting between Sunni and Brelvi . Do you know who started calling people Brelvi? If I am beeing called Brelvi I will first ask you why you are calling me that? If you can answer me then i'll go on with further information.
Patta hai i nahi kissi cheez ka our awain hi uth key lougon kou samjhane shuru hou jate hain?
The famous quote is to hold on to the biggest Jamaa' and Ahle Sunnah Wal Jamaa' is the biggest Jamaa' and you can bring out the earliest scholars/Alims from Ahle Sunnah and tell me if they were against Tasawwuf!
(And brother Cricket47 I haven't forget your message, I will answer you soon InshAllah.)
There is a point which we must make here, which is that praising Shaykh ‘Abd al-Qaadir does not mean praising everyone who claims to follow him. Not everyone who claims to follow a shaykh or a tareeqah or anything else is to be believed. How often has it happened that a person who is thought to be a true follower turned out to be the farthest removed from what was thought to be the case? How many misleading people don the cloak of asceticism and piety when they have nothing to do with either of them? Hence the Sufi tareeqah which is known nowadays as the Qaadiriyyah is not following the straight path which the Shaykh (may Allaah have mercy on him) followed, rather it is a deviant Sufi tareeqah which has deviated from the guidance of the Qur’aan and Sunnah; it exaggerates a great deal about Shaykh ‘Abd al-Qaadir and even attributes to him things that can only rightfully be attributed to Allaah. Some of them exaggerate concerning his grave, seeking help from it, and some of them exaggerate about his attributes and miracles (karaamah).
Sufism has numerous branches or tareeqahs, such as the Teejaniyyah, Qaadiriyyah, Naqshbandiyyah, Shaadhiliyyah, Rifaa’iyyah, etc., the followers of which all claim that their particular tareeqah is on the path of truth whilst the others are following falsehood. Islam forbids such sectarianism. Allaah says (interpretation of the meaning):
“… and be not of al-mushrikoon (the disbelievers in the Oneness of Allaah, polytheists, idolaters, etc),
Of those who split up their religion (i.e., who left the true Islamic monotheism), and became sects, [i.e., they invented new things in the religion (bid’ah) and followed their vain desires], each sect rejoicing in that which is with it.” [al-Room 30:31-32]
The Sufis worship others than Allaah, such as Prophets and “awliya’” [“saints”], living or dead. They say, “Yaa Jeelaani”, “Yaa Rifaa’i” [calling on their awliya’], or “O Messenger of Allaah, help and save” or “O Messenger of Allaah, our dependence is on you”, etc.
But Allaah forbids us to call on anyone except Him in matters that are beyond the person's capabilities. If a person does this, Allaah will count him as a mushrik, as He says (interpretation of the meaning):
“And invoke not, besides Allaah, any that will neither profit you, nor hurt you, but if (in case) you did so, you shall certainly be one of the zaalimoon (polytheists and wrongdoers).” [Yoonus 10:106]
The Sufis believe that there are abdaal, aqtaab and awliya’ (kinds of “saints”) to whom Allaah has given the power to run the affairs of the universe. Allaah tells us about the mushrikeen (interpretation of the meaning):
“Say [O Muhammad]: ‘…And who disposes the affairs?’ They will say. ‘Allaah.’…” [Yoonus 10:31]
The mushrik Arabs knew more about Allaah than these Sufis!
The Sufis turn to other than Allaah when calamity strikes, but Allaah says (interpretation of the meaning):
“And if Allaah touches you with harm, none can remove it but He, and if He touches you with good, then He is Able to do all things.” [al-An’aam 6:17]
Some Sufis believe in wahdat al-wujood (unity of existence). They do not have the idea of a Creator and His creation, instead they say that everything is creation and everything is god.
The Sufis advocate extreme asceticism in this life and do not believe in taking the necessary means or in jihaad, but Allaah says (interpretation of the meaning):
“But seek with that (wealth) which Allaah has bestowed on you, the home of the Hereafter, and forget not your portion of legal enjoyment in this world…” [al-Qasas 28:77]
“And make ready against them all that you can of power…” [al-Anfaal 8:60]
The Sufis refer the idea of ihsaan to their shaykhs and tell their followers to have a picture of their shaykh in mind when they remember Allaah and even when they are praying. Some of them even put a picture of their shaykh in front of them when they are praying. The Prophet (peace and blessings of Allaah be upon him) said: “Ihsaan is when you worship Allaah as if you can see Him, and although you cannot see Him, He can see you.” (Reported by Muslim).
The Sufis allow dancing, drums and musical instruments, and raising the voice when making dhikr, but Allaah says (interpretation of the meaning):
“The believers are only those who, when Allaah is mentioned, feel a fear in their hearts…” [al-Anfaal 8:2]
Moreover, you see some of them making dhikr by only pronouncing the Name of Allaah, saying, “Allaah, Allaah, Allaah.” This is bid’ah and has no meaning in Islam. They even go to the extreme of saying, “Ah, ah” or “Hu, Hu.” The Sunnah is for the Muslim to remember his Lord in words that have a true meaning for which he will be rewarded, such as saying Subhaan Allaah wa Alhamdulillah wa Laa ilaaha illa Allaah wa Allaahu akbar, and so on.
The Sufis recite love poems mentioning the names of women and boys in their dhikr gatherings, and they repeat words such as “love”, “passion”, “desire” and so on, as if they are in a gathering where people dance and drink wine and clap and shout. All of this has to do with the customs and acts of worship of the mushrikeen. Allaah says (interpretation of the meaning):
“Their salaah (prayer) at the House (of Allaah, i.e., the Ka’bah at Makkah) was nothing but whistling and clapping of hands…”
[al-Anfaal 8:35]
Some Sufis pierce themselves with rods of iron, saying, “O my grandfather!” So the shayaateen come to them and help them, because they are seeking the help of someone other than Allaah . Allaah says (interpretation of the meaning):
“And whosoever turns away (blinds himself) from the remembrance of the Most Beneficent (Allaah), We appoint for him a shaytaan (devil) to be a qareen (intimate companion) for him.”
[al-Zukhruf 43:36]
The Sufis claim to have gnosis and knowledge of the unseen, but the Qur’aan shows them to be liars. Allaah says (interpretation of the meaning):
“Say: ‘None in the heavens and the earth knows the ghayb (unseen) except Allaah…’” [al-Naml 27:65]
The Sufis claim that Allaah created the world for the sake of Muhammad (peace and blessings of Allaah be upon him), but the Qur’aan shows them to be liars. Allaah says (interpretation of the meaning):
“And I (Allaah) created not the jinns and humans except they should worship Me (Alone).” [al-Dhaariyaat 51:56]
Allaah, may He be glorified and exalted, addressed His Prophet (peace and blessings of Allaah be upon him) with the words (interpretation of the meaning):
“And worship your Lord until there comes unto the certainty (i.e., death).” [al-Hijr 15:99]
The Sufis claim that they can see Allaah in this life, but the Qur’aan shows them to be liars. Allaah says (interpretation of the meaning):
“[Moosa said:] ‘O my Lord! Show me (Yourself), that I may look upon You.’ Allaah said, ‘You cannot see Me…’” [al-A’raaf 7:143]
The Sufis claim that they take knowledge directly from Allaah, without the mediation of the Prophet (peace and blessings of Allaah be upon him) and in a conscious state (as opposed to dreams). So are they better than the Sahaabah??
The Sufis claim that they take knowledge directly from Allaah, without the mediation of the Prophet (peace and blessings of Allaah be upon him). They say, “Haddathani qalbi ‘an Rabbi (My heart told me from my Lord).”
The Sufis celebrate Mawlid and hold gatherings for sending blessings on the Prophet (peace and blessings of Allaah be upon him), but they go against his teachings by raising their voices in dhikr and anaasheed (religious songs) and qaseedahs (poems) that contain blatant shirk. Did the Prophet (peace and blessings of Allaah be upon him) celebrate his birthday? Did Abu Bakr, ‘Umar, ‘Uthman, ‘Ali, the four imaams or anyone else celebrate his birthday? Who knows more and is more correct in worship, the Prophet (peace and blessings of Allaah be upon him) and the Salaf, or the Sufis?
The Sufis travel to visit graves and seek blessings from their occupants or to make tawaaf (ritual circumambulation) around them or to make sacrifices at these sites, all of which goes against the teachings of the Prophet (peace and blessings of Allaah be upon him): “Do not travel to visit any place but three mosques: al-Masjid al-Haraam [in Makkah], this mosque of mine [in Madeenah] and al-Masjid al-Aqsa [in Jerusalem].” (Agreed upon).
The Sufis are blindly loyal to their shaykhs, even when what they go against the words of Allaah and His Messenger. But Allaah, may He be exalted, says (interpretation of the meaning):
“O you who believe! Do not put (yourselves) forward before Allaah and His Messenger…” [al-Hujuraat 49:1]
The Sufis use talismans, letters and numbers for making decisions and for making amulets and charms and so on.
The Sufis do not restrict themselves to the specific blessings on the Prophet (peace and blessings of Allaah be upon him) that were narrated from him. They invented new formulas that involve seeking his blessings and other kinds of blatant shirk which are unacceptable to the one on whom they are sending blessings.
This will take some time to read but I urge you to look through this.
There are certain question marks over his credibility also. By his very own student. 
