Sufism

Alchemy of the heart transmutes the base metal of the self into gold through discipline and love

Ghazali borrows the vocabulary of medieval alchemy, transmuting base metal into gold, to describe spiritual discipline as a precise technical process rather than a vague aspiration.

The Kimiya-yi Sa'adat is al-Ghazali's own Persian-language digest of the much longer Arabic Ihya Ulum al-Din, written to bring the same teaching to a broader audience beyond the scholarly elite who could read his major work. In its introduction, he sets up the extended alchemy metaphor deliberately: just as the alchemist's art was believed to require exact knowledge of the base substance, the desired substance, the method of transformation, and the impurities to be removed, spiritual self-transformation likewise requires knowing one's own qualities, the character one is meant to become, the disciplines that produce the change, and the obstacles of ego and heedlessness that must be burned away. The metaphor is not decorative; Ghazali structures much of the book's practical guidance around this four-part scheme rather than leaving it as a poetic flourish. Its usefulness was pedagogical: alchemy was a widely understood technical art in his time, and mapping spiritual work onto it made an otherwise abstract process legible as a craft with steps that could actually be learned.

Kimiya-yi Sa'adat (The Alchemy of Happiness)