The work of the polisher will not succeed upon it, and the rust cannot be extracted from it except by returning it to the fire. Likewise, souls of accidental turbidity are cleared by reminders and exhortations, thus remembering their past states. As for the natural souls that are heavy with filth and turbidity, nothing can clear them except their entry into the rank of torment, the length of their stay within it, and their repeated return to it.
O soul: How many times must gold that is heavily alloyed with base metals be returned to the fire before it becomes pure and refined? How many times must the crooked wood be placed into the fire and straightened before it becomes upright? How many times must the wheat be returned to the sieves before its impurities 1 are removed? And how many times must the wicked, rusted souls face colors of torment before they become upright and return [to their origin]?
O soul: It is impossible for anyone to know the excellence of the honey's sweetness over the bitterness of aloes without tasting them both and comprehending them through discernment. Likewise, it is impossible for the soul to know the excellence of the sweetness of bliss over the bitterness of torment without tasting them both and comprehending them intellectually.