Khawaja Farid uddin Masud Shakar Ganj (Allah have mercy on him) (d. 1266 CE. Pakpattan) instructed his deputies (khulafa),
‘The spiritual progress lies in the discipline of the soul and the purification of inner self, and not in the mechanical performance of worship (only).
If marifat is desired, then anger, jealousy and hatred should be completely wiped out from the heart.
Religious knowledge and learning are pre-requisite to spiritual discipline.”
Contribution of Mazahir-e-Uloom of Saharanpur to Tasawwuf, Dr Iffat Javed’s Ph.D thesis, Jamia Millia, Dehli, page 15 (edited)