On my first journey I found a kind of knowledge acceptable to both the elect and the common folk, on the second, knowledge acceptable to the elect and not the common folk, and on the third, knowledge acceptable to neither the elect nor the common folk; thus I remained an outcast and alone. The first kind of knowledge was repentance, which both the elect and the common folk accept, the second was trust in God and fellowship with Him and love, which the elect accept, and the third was the knowledge of reality, which is beyond the power of human learning and reason to attain, so men reject it.

(Dhu-l-Nun)