Original sentence: Shaykh Ahmad Zarruq, a 14th century Sufi who wrote "The Principles of Sufism" defined Sufism as, "a science whose objective is the reparation of the heart and turning it away from all else but God.”  Ibn 'Ajiba, one of the best known Sufi masters defined Sufism as "a science through which one can know how to travel into the presence of the Divine, purify one’s inward from filth and beautify it with a variety of praiseworthy traits
Edited sentence: Shaykh Ahmad Zarruq, a 14th century Sufi who wrote "The Principles of Sufism" defined Sufism as, "a science (this is a belief system or method, not a true science) whose objective is the reparation of the heart and turning it away from all else but God.”  Ibn 'Ajiba, one of the best known Sufi masters defined Sufism as "a science (this is a belief system, not a true science) through which one can know how to travel into the presence of the Divine, purify one’s inward from filth and beautify it with a variety of praiseworthy traits