"The food of hearts is wisdom, knowledge of Allah, and love of Him. The heart's turning away from its natural disposition is the result of illnesses that afflict it, as when an illness afflicts a person's stomach, causing him not to desire food or drink though they are a means for his survival. Accordingly, every heart that inclines to love of other than Allah has a sickness to extent of its inclination. The only exception is if it loved that thing as a means to the love of Allah and His religion. This is subtle, however, and only know by those of spiritual insight. The opinion of the one afflicted is of little consequence in this, unless confirmed by his spiritual guide."
- Taken from Sufism and Good Character by Imam Zafar ‘Uthmani, translated by Faraz F. Rabbani (p.29.)