Jalaluddin Rumi, Masnavi I Ma'navi — Book IV
“ To the regarder of externals, genuine and base coin are alike. How can he know what is inside the basket? Many are the gold coins made black with smoke, So that they elude the clutches of greedy thieves; Many are the copper coins gilded with gold, And sold as gold to men of slender wits. We who regard the inside of the world, We look at the heart and disregard the outside. ”
