The Christian tradition speaks of fire as a purification process. Other ancient traditions also speak of the heart on fire, with purification as a necessary step. In Dante’s Divine Comedy, fire and suffering are seen as a means of both purification and transformation. An angels speaks, in canto 27 of the Purgatorio:

Holy souls, you cannot move ahead unless the fire’s stung you first…
Enter the flames and don’t be deaf to song you’ll hear beyond.

~ Dante, The Divine Comedy
Virgil leads the pilgrim Dante through the wall of “refining fire,” and Dante emerges a new man. He no longer needs the guidance of Virgil, who tells him, “I invest thee then with crown and mitre, sovereign over thyself.”

At the end of The Purgatorio, the pilgrim Dante, reunited with Beatrice, who personifies love. Here he finds himself “regenerate, even as new plans renewed with foliage new, and made ready for mounting to the stars.”

Other Christian mystics and teachers refer to fire and suffering:

The fire that is God does indeed devour but it does not debase.
~ Bernard of Clairvaux

By going out of yourself and everything, casting aside every restraint in pure and absolute ecstasy, you raise yourself to the ray of Divine Darkness that is beyond being.
~ Denis the Areopagite

If you do not die before you die, you die when you die. By aligning itself with God’s will, a soul takes on the taste of God. Grief and joy, bitterness and sweetness, darkness and light, all become divine.
~ Meister Eckhart

You were iron, but fire has burned the rust off you.
~ Amma Syncletica, a Desert Mother

I return from flames of fire; tried and pure and white.
~ William Blake

A man should do everything he can on his side to purify his heart, using virtues as tools for this purpose; but without the fire of the Spirit, everything he does will remain inactive.
~ Philokalia

From the stories of the Desert Fathers:

Abba Lot came to Abba Joseph and said: Father, according as I am able, I keep my little rule, and my little fast, my prayer, meditation and contemplative silence; and, according as I am able, I strive to cleanse my heart of thoughts: now what more should I do? The elder rose up in reply and stretched out his hands to heaven, and his fingers became like ten lamps of fire.
He said: You must become entirely flame.