It is said that Dhu-ul-Nun walked past some doctors one day. Around them were a lot of folk, men and women, holding bottles of urine in their hands. The doctors were writing out prescriptions for them all, suitable for the disease which each one had.
Said Dhu-ul Nun: I drew near to a doctor and saluted him and he returned my salutation. Then said I to him: May Allah have mercy upon you, pray give me a remedy for sin. The doctor lowered his head for the space of an hour and then raising it said: If I prescribe for you a medicine, will you give me your attention and understanding? And I replied: Yes, Allah willing.
Then said the doctor: Take the root of poverty with the pollen of patience with the myrobalan of submission and the belleric of concentration on Allah together with the tamarinds of humility and the polypody of sincerity, the rhubarb of purity, and the agaricum of fidelity. Put all these into the cauldron of sinlessness. Set beneath them the fire of devotion until the bubbles of wisdom froth up. When these bubbles of wisdom appear, sieve them in the sieve of remembrance. Then strain into the goblet of acceptance. Fan with the fan of the praise of Allah until cool. When cold, drink and taste the temperance therein. Thereafter never will you commit sin. So treat your heart with these medicines just as you treat your body with those drugs. Thus will you enjoy perfect and complete restoration to health both in this World and the next. And verily there is no power but Allah, the High, the Great.