But as it is in mockery that Celsus says we speak of “God coming down like a torturer bearing fire,” and thus compels us unseasonably to investigate words of deeper meaning, we shall make a few remarks, sufficient to enable our hearers to form an idea of the defence which disposes of the ridicule of Celsus against us, and then we shall turn to what follows. The divine word says that our God is “a consuming fire,” and that “He draws rivers of fire before Him;” nay, that He even enters in as “a refiner's fire, and as a fuller's herb,” to purify His own people.
But when He is said to be a “consuming fire,” we inquire what are the things which are appropriate to be consumed by God. And we assert that they are wickedness, and the works which result from it, and which, being figuratively called “wood, hay, stubble,” God consumes as a fire. The wicked man, accordingly, is said to build up on the previously-laid foundation of reason, “wood, and hay, and stubble.” If, then, any one can show that these words were differently understood by the writer, and can prove that the wicked man literally builds up “wood, or hay, or stubble,” it is evident that the fire must be understood to be material, and an object of sense.
But if, on the contrary, the works of the wicked man are spoken of figuratively under the names of “wood, or hay, or stubble,” why does it not at once occur (to inquire) in what sense the word “fire” is to be taken, so that “wood” of such a kind should be consumed? For (the Scripture) says: “The fire will try each man's work of what sort it is. If any man's work abide which he has built thereupon, he shall receive a reward. If any man's work be burned, he shall suffer loss.” But what work can be spoken of in these words as being “burned,” save all that results from wickedness?
Therefore our God is a “consuming fire” in the sense in which we have taken the word; and thus He enters in as a “refiner's fire,” to refine the rational nature, which has been filled with the lead of wickedness, and to free it from the other impure materials, which adulterate the natural gold or silver, so to speak, of the soul. And, in like manner, “rivers of fire” are said to be before God, who will thoroughly cleanse away the evil which is intermingled throughout the whole soul. But these remarks are sufficient in answer to the assertion, “that thus they were made to give expression to the erroneous opinion that God will come down bearing fire like a torturer.”
Source: Against Celsus (New Advent)