From the Discourse on the Resurrection

VIII. But it is not satisfactory to say that the universe will be utterly destroyed, and sea and air and sky will be no longer. For the whole world will be deluged with fire from heaven, and burnt for the purpose of purification and renewal; it will not, however, come to complete ruin and corruption. For if it were better for the world not to be than to be, why did God, in making the world, take the worse course? But God did not work in vain, or do that which was worst. God therefore ordered the creation with a view to its existence and continuance, as also the Book of Wisdom confirms, saying, “For God created all things that they might have their being; and the generations of the world were healthful, and there is no poison of destruction in them.” And Paul clearly testifies this, saying, “For the earnest expectation of the creature waits for the manifestation of the sons of God. For the creature was made subject to vanity, not willingly, but by reason of him that subjected the same in hope: because the creature itself also shall be delivered from the bondage of corruption into the glorious liberty of the children of God.” For the creation was made subject to vanity, he says, and he expects that it will be set free from such servitude, as he intends to call this world by the name of creation. For it is not what is unseen but what is seen that is subject to corruption. The creation, then, after being restored to a better and more seemly state, remains, rejoicing and exulting over the children of God at the resurrection; for whose sake it now groans and travails, waiting itself also for our redemption from the corruption of the body, that, when we have risen and shaken off the mortality of the flesh, according to that which is written, “Shake off the dust, and arise, and sit down, O Jerusalem,” and have been set free from sin, it also shall be freed from corruption and be subject no longer to vanity, but to righteousness. Isaiah says, too, “For as the new heaven and the new earth which I make, remains before me, says the Lord, so shall your seed and your name be;” and again, “Thus says the Lord that created the heaven, it is He who prepared the earth and created it, He determined it; He created it not in vain, but formed it to be inhabited.” For in reality God did not establish the universe in vain, or to no purpose but destruction, as those weak-minded men say, but to exist, and be inhabited, and continue. Wherefore the earth and the heaven must exist again after the conflagration and shaking of all things.

IX. But if our opponents say, How then is it, if the universe be not destroyed, that the Lord says that “heaven and earth shall pass away;” and the prophet, that “the heaven shall perish as smoke, and the earth shall grow old as a garment;” we answer, because it is usual for the Scriptures to call the change of the world from its present condition to a better and more glorious one, destruction; as its earlier form is lost in the change of all things to a state of greater splendour; for there is no contradiction nor absurdity in the Holy Scriptures. For not “the world” but the “fashion of this world” passes away, it is said; so it is usual for the Scriptures to call the change from an earlier form to a better and more comely state, destruction; just as when one calls by the name of destruction the change from a childish form into a perfect man, as the stature of the child is turned into manly size and beauty. We may expect that the creation will pass away, as if it were to perish in the burning, in order that it may be renewed, not however that it will be destroyed, that we who are renewed may dwell in a renewed world without taste of sorrow; according as it is said, “When You let Your breath go forth, they shall be made, and You shall renew the face of the earth;” God henceforth providing for the due temperature of that which surrounds it. For as the earth is to exist after the present age, there must be by all means inhabitants for it, who shall no longer be liable to death, nor shall marry, nor beget children, but live in all happiness, like the angels, without change or decay. Wherefore it is silly to discuss in what way of life our bodies will then exist, if there is no longer air, nor earth, nor anything else.

X. But in addition to what has been said, there is this point worth consideration, since it misleads very much, if we may be outspoken about matters of such importance, Aglaophon For you said that the Lord declared plainly that those who shall obtain the resurrection shall then be as the angels. You brought this objection: The angels, being without flesh, are on this account in the utmost happiness and glory. We must then, as we are to be made equal to the angels, be like them stripped of flesh, and be angels. But you overlooked this, my excellent friend, that He who created and set in order the universe out of nothing, ordained the nature of immortal beings to be distributed not only among angels and ministers, but also among principalities, and thrones, and powers. For the race of angels is one, and that of principalities and powers another; because immortal beings are not all of one order, and constitution, and tribe, and family, but there are differences of race and tribe. And neither do the cherubim, departing from their own nature, assume the form of angels; nor, again, do angels assume the form of the others. For they cannot be anything but what they are and have been made. Moreover, man also having been appointed by the original order of things to inhabit the world, and to rule over all that is in it, when he is immortal, will never be changed from being a man into the form either of angels or any other; for neither do angels undergo a change from their original form to another. For Christ at His coming did not proclaim that the human nature should, when it is immortal, be remoulded or transformed into another nature, but into what it was before the fall. For each one among created things must remain in its own proper place, that none may be wanting to any, but all may be full: heaven of angels, thrones of powers, luminaries of ministers; and the more divine spots, and the undefiled and untainted luminaries, with seraphim, who attend the Supreme Council, and uphold the universe; and the world of men. For if we granted that men are changed into angels, it would follow that we say that angels also are changed into powers, and these into one thing and the other, until our argument proceed too far for safety.

XI. Neither did God, as if He had made man badly, or committed a mistake in the formation of him, determine afterwards to make an angel, repenting of His work, as the worst of craftsmen do; nor did He fashion man, after He had wished originally to make an angel, and failed; for this would be a sign of weakness, etc. Why even then did He make man and not angels, if He wished men to be angels and not men? Was it because He was unable? It is blasphemy to suppose so. Or was He so busy in making the worse as to loiter about the better? This too is absurd. For He does not fail in making what is good, nor defers it, nor is incapable of it; but He has the power to act how and when He pleases, inasmuch as He is Himself power. Wherefore it was because He intended man to be man, that He originally made him so. But if He so intended— since He intends what is good— man is good. Now man is said to be composed of soul and body; he cannot then exist without a body, but with a body, unless there be produced another man besides man. For all the orders of immortal beings must be preserved by God, and among these is man. “For,” says the Book of Wisdom, “God created man to be immortal, and made him to be an image of His own eternity.” The body then perishes not; for man is composed of soul and body.