On its own, coal is nothing lovely. It’s inert, dusty, and cold. But it has this capacity: It can burn. In fact, it might be said that coal is created to burn, that receiving flame is the telos, the destiny of coal. The Holy Spirit likewise comes to burn within us, though we don’t deserve it, and we bring nothing of beauty to the process. Our main task is to get out of the way, to remove impurities bit by bit so that one day we can be wholly engulfed by divine fire, and become a living flame of love. This is theosis. (Frederica Mathewes-Green, The Illumined Heart)
Theosis, or deification, is a key theme in Eastern Christianity. It bears similarity to the Wesleyan emphasis on holiness and Christian perfection.
Good connection between Wesleyan and Orthodox themes. A great, thorough, but difficult treatment of this theme is Orthodox Spirituality by Dmitri Staniloe. A good thought for Lent, also.