St. Gregory of Nyssa: "The purging fire"

“WHEN he has quitted his body and the difference between virtue and vice is known he cannot approach God till the purging fire shall have cleansed the stains with which his soul was infested. That same fire in others will cancel the corruption of matter, and the propensity to evil.”

~St. Gregory of Nyssa (c. 335 – c. 395): PG 46, 524.
 

Icon of St. Gregory of Nyssa;
14th cent. fresco, Chora Church, Istanbul.