On the contrary, It is written ( Ps. 49:3 ): "A fire shall burn before Him, and a mighty tempest shall be around Him"; and afterwards in reference to the judgment ( Ps. 49:4 ): "He shall call heaven from above, and the earth to judge His people." Therefore it would seem that the final cleansing of the world will be by means of fire.
Further, it is written ( 2 Pet. 3:12 ): "The heavens being on fire will be dissolved, and the elements shall melt with the burning heat." Therefore this cleansing will be effected by fire.
I answer that, As stated above (A[1]) this cleansing of the world will remove from it the stain contracted from sin, and the impurity resulting from mixture, and will be a disposition to the perfection of glory; and consequently in this threefold respect it will be most fitting for it to be effected by fire. First, because since fire is the most noble of the elements, its natural properties are more like the properties of glory, and this is especially clear in regard to light. Secondly, because fire, on account of the efficacy of its active virtue, is not as susceptible as the other elements to the admixture of a foreign matter. Thirdly, because the sphere of fire is far removed from our abode; nor are we so familiar with the use of fire as with that of earth, water, and air, so that it is not so liable to depreciation. Moreover, it is most efficacious in cleansing and in separating by a process of rarefaction.
Reply to Objection 1: Fire is not employed by us in its proper matter (since thus it is far removed from us), but only in a foreign matter: and in this respect it will be possible for the world to be cleansed by fire as existing in its pure state. But in so far as it has an admixture of some foreign matter it will be possible for it to be cleansed; and thus it will be cleanser and cleansed under different aspects. and this is not unreasonable.
Reply to Objection 2: The first cleansing of the world by the deluge regarded only the stain of sin. Now the sin which was most prevalent then was the sin of concupiscence, and consequently it was fitting that the cleansing should be by means of its contrary, namely water. But the second cleansing regards both the stain of sin and the impurity of mixture, and in respect of both it is more fitting for it to be effected by fire than by water. For the power of water tends to unite rather than to separate; wherefore the natural impurity of the elements could not be removed by water as by fire. Moreover, at the end of the world the prevalent sin will be that of tepidity, as though the world were already growing old, because then, according to Mat. 24:12, "the charity of many shall grow cold," and consequently the cleansing will then be fittingly effected by fire. Nor is there any thing that cannot in some way be cleansed by fire: some things, however, cannot be cleansed by fire without being destroyed themselves, such as cloths and wooden vessels, and these the Law ordered to be cleansed with water; yet all these things will be finally destroyed by fire.
Reply to Objection 3: By the work of distinction things received different forms whereby they are distinct from one another: and consequently this could only be done by Him Who is the author of nature. But by the final cleansing things will be restored to the purity wherein they were created, wherefore created nature will be able to minister to its Creator to this effect; and for this reason is a creature employed as a minister, that it is ennobled thereby.
Whether the fire whereby the world will be cleansed will be of the same species with elemental fire?
Objection 1: It would seem that the fire in question is not of the same species as elemental fire. For nothing consumes itself. But that fire will consume the four elements according to a gloss on 2 Pet. 3:12. Therefore that fire will not be of the same species as elemental fire.
Objection 2: Further, as power is made known by operation, so is nature made known by power. Now that fire will have a different power from the fire which is an element: because it will cleanse the universe, whereas this fire cannot do that. Therefore it will not be of the same species as this.
Objection 3: Further, in natural bodies those that are of the same species have the same movement. But that fire will have a different movement from the fire that is an element, because it will move in all directions so as to cleanse the whole. Therefore it is not of the same species.
On the contrary, Augustine says (De Civ. Dei xx, 16), and his words are contained in a gloss on 1 Cor. 7:31, that "the fashion of this world will perish in the burning of worldly flames." Therefore that fire will be of the same nature as the fire which is now in the world.
Further, just as the future cleansing is to be by fire, so was the past cleansing by water: and they are both compared to one another, 2 Pet. 3:5. Now in the first cleansing the water was of the same species with elemental water. Therefore in like manner the fire of the second cleansing will be of the same species with elemental fire.
I answer that, We meet with three opinions on this question. For some say that the element of fire which is in its own sphere will come down to cleanse the world: and they explain this descent by way of multiplication, because the fire will spread through finding combustible matter on all sides. And this will result all the more then since the virtue of the fire will be raised over all the elements. Against this, however, would seem to be not only the fact that this fire will come down, but also the statement of the saints that it will rise up; thus ( 2 Pet. 3:10 ) it is declared that the fire of the judgment will rise as high as the waters of the deluge; whence it would seem to follow that this fire is situated towards the middle of the place of generation. Hence others say that this fire will be generated towards the intervening space through the focusing together of the rays of the heavenly bodies, just as we see them focused together in a burning-glass; for at that time in lieu of glasses there will be concave clouds, on which the rays will strike But this again does not seem probable: for since the effects of heavenly bodies depend on certain fixed positions and aspects, if this fire resulted from the virtue of the heavenly bodies, the time of this cleansing would be known to those who observe the movements of the stars and this is contrary to the authority of Scripture. Consequently others, following Augustine, say that "just as the deluge resulted from an outpouring of the waters of the world, so the fashion of this world will perish by a burning of worldly flames" (De Civ. Dei. xx, 16). This burning is nothing else but the assembly of all those lower and higher causes that by their nature have a kindling virtue: and this assembly will take place not in the ordinary course of things, but by the Divine power: and from all these causes thus assembled the fire that will burn the surface of this world will result. If we consider aright these opinions, we shall find that they differ as to the cause producing this fire and not as to its species. For fire, whether produced by the sun or by some lower heating cause, is of the same species as fire in its own sphere, except in so far as the former has some admixture of foreign matter. And this will of necessity be the case then, since fire cannot cleanse a thing, unless this become its matter in some way. Hence we must grant that the fire in question is simply of the same species as ours.
Reply to Objection 1: The fire in question, although of the same species as ours, is not identically the same. Now we see that of two fires of the same species one destroys the other, namely the greater destroys the lesser, by consuming its matter. In like manner that fire will be able to destroy our fire.
Reply to Objection 2: Just as an operation that proceeds from the virtue of a thing is an indication of that virtue, so is its virtue an indication of its essence or nature, if it proceed from the essential principles of the thing. But an operation that does not proceed from the virtue of the operator does not indicate its virtue. This appears in instruments: for the action of an instrument shows forth the virtue of the mover rather than that of the instrument, since it shows forth the virtue of the agent in so far as the latter is the first principle of the action, whereas it does not show forth the virtue of the instrument, except in so far as it is susceptive of the influence of the principal agent as moving that instrument. In like manner a virtue that does not proceed from the essential principles of a thing does not indicate the nature of that thing except in the point of susceptibility. Thus the virtue whereby hot water can heat is no indication of the nature of water except in the point of its being receptive of heat. Consequently nothing prevents water that has this virtue from being of the same species as water that has it not. In like manner it is not unreasonable that this fire, which will have the power to cleanse the surface of the world, will be of the same species as the fire to which we are used, since the heating power therein arises, not from its essential principles but from the divine power or operation: whether we say that this power is an absolute quality, such as heat in hot water, or a kind of intention as we have ascribed to instrumental virtue (Sent. iv, D, 1, qu. 1, A[4]) [*Cf. TP, Q[62], A[4], ad 1]. The latter is more probable since that fire will not act save as the instrument of the Divine power.
Reply to Objection 3: Of its own nature fire tends only upwards; but in so far as it pursues its matter, which it requires when it is outside its own sphere, it follows the site of combustible matter. Accordingly it is not unreasonable for it to take a circular or a downward course, especially in so far as it acts as the instrument of the Divine power.
Whether that fire will cleanse also the higher heavens?
Objection 1: It would seem that that fire will cleanse also the higher heavens. For it is written ( Ps. 101:26 , 27 ): "The heavens are the works of Thy hands: they shall perish but Thou remainest." Now the higher heavens also are the work of God's hands. Therefore they also shall perish in the final burning of the world.
Objection 2: Further, it is written ( 2 Pet. 3:12 ): "The heavens being on fire shall be dissolved, and the elements shall melt with the burning heat of fire." Now the heavens that are distinct from the elements are the higher heavens, wherein the stars are fixed. Therefore it would seem that they also will be cleansed by that fire.
Objection 3: Further, the purpose of that fire will be to remove from bodies their indisposition to the perfection of glory. Now in the higher heaven we find this indisposition both as regards guilt, since the devil sinned there, and as regards natural deficiency, since a gloss on Rom. 8:22, "We know that every creature groaneth and is in labor even until now," says: "All the elements fulfill their duty with labor: even as it is not without labor that the sun and moon travel their appointed course." Therefore the higher heavens also will be cleansed by that fire.
On the contrary, "The heavenly bodies are not receptive of impressions from without" [*Cf. Sent. Philosop. ex Arist. collect. lit. c.---Among the works of Bede].
Further, a gloss on 2 Thess. 1:8, "In a flame of fire giving vengeance," says: "There will be in the world a fire that shall precede Him, and shall rise in the air to the same height as did the waters of the deluge." But the waters of the deluge did not rise to the height of the higher heavens but only 15 cubits higher than the mountain summits ( Gn. 7:20 ). Therefore the higher heavens will not be cleansed by that fire.
I answer that, The cleansing of the world will be for the purpose of removing from bodies the disposition contrary to the perfection of glory, and this perfection is the final consummation of the universe: and this disposition is to be found in all bodies, but differently in different bodies. For in some this indisposition regards something inherent to their substance: as in these lower bodies which by being mixed together fall away from their own purity. In others this indisposition does not regard something inherent to their substance; as in the heavenly bodies, wherein nothing is to be found contrary to the final perfection of the universe, except movement which is the way to perfection, and this not any kind of movement, but only local movement, which changes nothing intrinsic to a thing, such as its substance, quantity, or quality, but only its place which is extrinsic to it. Consequently there is no need to take anything away from the substance of the higher heavens, but only to set its movement at rest. Now local movement is brought to rest not by the action of a counter agent, but by the mover ceasing to move; and therefore the heavenly bodies will not be cleansed, neither by fire nor by the action of any creature, but in lieu of being cleansed they will be set at rest by God's will alone.
Reply to Objection 1: As Augustine says (De Civ. Dei xx, 18,24): "Those words of the psalm refer to the aerial heavens which will be cleansed by the fire of the final conflagration." Or we may reply that if they refer also to the higher heavens, these are said to perish as regards their movement whereby now they are moved without cessation.
Reply to Objection 2: Peter explains himself to which heavens he refers. For before the words quoted, he had said ( 2 Pet. 3:5-7 ): "The heavens . . . first, and the earth . . . through water . . . perished . . . which . . . now, by the same word are kept in store, reserved unto fire unto the day of judgment." [*The entire text differs somewhat from St. Thomas's quotation; but the sense is the same.] Therefore the heavens to be cleansed are those which before were cleansed by the waters of the deluge, namely the aerial heavens.