Sufism means drawing near to Allah through knowledge and action. Thus, the Sufi is the one drawn near. Today, in the Islamic lands, this title is generally applied not to the one drawn near to Allah, but rather to those who cling to certain outward manners and forms. Moreover, how many people close to Allah in the lands are not known as Sufis, simply because they do not adorn themselves in the garb of the Sufis?
Sufism is a branch of the Sacred Law [fiqh], since the Sacred Law entails knowing the self, and what is for it and against it, as is reported from Abū Ḥanīfa (may Allah have mercy on him). It is clear that knowing the way to draw closer to Allah through knowledge and works is not only part of Sacred Law – it is the very essence of Sacred Law. Thus, the jurist [faqīh] is he who has drawn near to Allah by knowledge coupled with actions, not merely by the knowledge of legal rulings and their proofs. Such a jurist is what is meant by the Prophet (peace be upon him)’s words: ‘A single jurist is harder on Satan than a thousand worshippers’. (Tirmidhī & Ibn Māja)
That is the jurist who acts upon his knowledge of Sacred Law, and draws near to Allah through his knowledge and actions. Allah Most High said, ‘Only the knowledgeable of Allah’s servants fear Him’ (Qur’ān 35:28)
He said, ‘Only the knowledgeable…’ thereby negating the possibility of [true] knowledge and deep understanding [fiqh] for those who do not fear Allah. It thus became clear to scholars who seek the next life that the path to divine knowledge and stations of proximity is closed off except to thos who possess renunciation [zuhd] and piety [taqwa].
Hence, through piety and high levels of renunciation does a servant become immersed in both knowledge and action. This is the essence of Sufism. The one who realises this is a true Sufi.
[Sufism & Good Character, Imām Ẓafar Uthmānī, pg. 7 – 8]