A lot of people have misunderstandings about tasawwuf. Many think that it is something beyond Qur'an and Sunnah. Errant Sufis as well as the superficial ulema, although on the opposite ends of the spectrum, are together in holding this mistaken notion. Consequently the first group has shunned the Qur'an and Hadith while the second group has shunned tasawwuf.
Actually, although the term tasawwuf, like many other religious terms in use today, evolved later, the discipline is very much part of the Shariah. The department of the Shariah relating to external deeds like salat and zakat is called fiqh while the one dealing with the internal feelings and states of the heart is called tasawwuf. Both are commanded in the Qur'an.
Thus while commanding Salat and Zakat, the Qur'an also commands gratefulness and love of Allah and condemns the evil of pride and vanity. Similarly, in the books of hadith, along with the chapters on Ibadat, trade and commerce, marriage and divorce, are to be found the chapters on riya (showoff) takabbur, akhlaq, etc. These commands are as much a mandatory requirement as the ones dealing with external deeds.
On reflection it will be realized that all the external deeds are designed for the reformation of the heart. That is the basis of success in the hereafter while its despoiling is the cause of total destruction. This is precisely what is known technically as tasawwuf. Its focus is tahzeebe akhlaq or the adornment of character; its motive is the attainment of Divine pleasure; its method is total obedience to the commands of the Shariah.
Tasawwuf is the soul of Islam. Its function is to purity the heart from the lowly bestial attributes of lust, calamities of the tongue, anger, malice, jealousy, love of the world, love of fame, niggardliness, greed, ostentation, vanity, deception, etc. At the same time it aims at the adornment of the heart with the lofty attributes of repentance, perseverance, gratefulness, fear of Allah, hope, abstention, tauheed, trust, love, sincerity, truth, contemplation, etc.
[Condensed from writings of Maulana Ashraf Ali Thanvi]
From an article written by Khalid Baig in AlbalaghTo read the full article click here