The role of the spiritual mentor is essential in the practice of Tasawwuf. Tasawwuf is the traditional Islamic science of self-improvement and spirituality (sufism), focussing on one's relationship with Allah. The Revivalry blog explains the practice:

 

 

Hence, when one turns to a Spiritual Mentor, it is to reform oneself, and that is the real objective of turning to him is achieved: to imbibe excellent traits, and ward off and crush the unworthy characteristics. This, then, is the true purpose of Tasawwuf. Nevertheless, the Zikr and supplications are also helpful to the seeker. Only through the guidance of the Spiritual Mentor can the regimen of Zikr, supplications and other repetitions be prescribed for every individual according to the Sheikh's opinion of his condition.

You can read more about Tasawwuf and the need for a spiritual mentor here.