Gregory the Great — on Ezek 1:4 (Homilies on Ezekiel, Book 1, Homily 2)

“But what followed from that darkness of the great cloud is added, when it immediately says: "And fire enveloping." For by the name of fire, when it is spoken through signification, sometimes the Holy Spirit is designated, and sometimes the malice of the mind. For concerning good fire it is written: "I have come to cast fire upon the earth; and what do I desire, except that it be kindled?" For fire is cast upon the earth when the earthly mind, breathed upon by the ardor of the Holy Spirit, is consumed away from its carnal desires. But concerning evil fire it is said: "And now fire shall consume the adversaries," because the most wicked heart wastes away from its own malice. Moreover, just as the fire of love raises up the mind, so the fire of malice envelops it, because the Holy Spirit elevates the heart which it fills, and the ardor of malice always bends it toward lower things. Therefore Judea, blinded by the cloud of her ignorance, because she soon burst forth into the wickedness of persecution, was enveloped by her own fire, she who entangled herself in the bond of wickedness through that very cruelty with which she burned. "And a wind of whirlwind was coming from the North, and a great cloud, and fire enveloping," because having been led from the coldness of her torpor into the darkness of ignorance, she burst forth even unto the malice of persecution. Whence it is also said to another prophet: "What do you see?" Who immediately responded: "I see a boiling pot, and its face is from the face of the North." For the mind of the Jews, raging in persecution and rolling waves of thoughts in the cruelty of malice, what else was it but a boiling pot? Its face is said to be from the face of the North, because if she had not subjected herself to the adversary spirit through torpor of mind, she would not have burned against good people in such great malice. Therefore fire enveloping follows the cloud, because in them the cruelty of persecution followed the blindness of mind. For if they had known, they would never have crucified the Lord of glory.”