So great a good is peace that even when earthly and mortal affairs are in question no other word is heard with more pleasure, nothing else is desired with greater longing, and finally nothing better can be found. So if we choose to speak about it at a little greater length, we shall not be tedious to our readers, I think, both because our theme is the end of this city and because of the very sweetness of peace, which is dear to all.
Peace: A Universal Aspiration [XIX, 12]
Whoever reviews at all, with me, the pattern of human affairs and our common nature observes that just as there is no man who does not wish joy, so there is no man who does not wish peace. 
Peace: Tranquillity of the Order [XIX, 13]
1. The peace of the body is an ordered proportionment of its components; the peace of the irrational soul is an ordered repose of the appetites; the peace of the rational soul is the ordered agreement of knowledge and action. The peace of body and soul is the ordered life and health of a living creature; peace between mortal man and God is an ordered life obedience in the faith under an everlasting law; peace between men is on ordered agreement of mind; domestic peace is an ordered agreement among those who dwell together concerning command and obedience; the peace of the heavenly city is a perfectly ordered and fully concordant fellowship in the enjoyment of God; the peace of all things is a tranquillity of order. Order is the classification of things equal and unequal that assigns to each its proper position.
Therefore the wretched for, in so far as they are wretched, they certainly are not in a state of peace, lack the tranquillity of order, in which there is no tumultuous activity; nevertheless, because they are deservedly and justly wretched, in that very wretchedness of theirs they are still unable to escape from the realm of order. Though they are not indeed united with the blessed, yet it is by a law of order that they are separated from them. And when they are free from tumultuous activity, they are adjusted to their condition, no matter how slightly.
Hence there is among them some tranquillity of order, and therefore there is among them some peace. But they are wretched because, although they are to some degree free from anxiety and suffering, they are not in such a case as could justify their being free from anxiety and suffering. Still more wretched are they, however, if they are not at peace with that law by which the natural order is administered. But when they suffer, their peace is embroiled in the part that suffers; but in the part where there is no torment of pain and the frame of nature is not dissolved, peace still abides.
Just as there can be life, then, without pain, while there can be no pain without life, so, too, there can be peace without any war, but no war without some sort of peace. This does not follow from the nature of war, but because war is waged by or within persons who have some natural being, for they could not exist if they were not some sort of peace to hold them together. This does not follow from the nature of war, but because war is waged by or within persons who have some natural being, for they could not exist if there were not some sort of peace to hold them together.
2. Therefore there is a nature in which there is no evil, nay, in which no evil can even exist; but there cannot be a nature in which there is no good. Hence not even the nature of the devil himself is evil so far as it s nature; but perversity makes it evil. So he did not stand steadfast in the truth, yet did not escape the judgement of the truth; he did not remain in the tranquillity of order, yet did not thereby flee from the power of the ordainer. The goodness of God, imparted to his nature, does not remove him from the justice of God, which ordains his punishment; nor does God thereby punish the good that He has created, but the evil that the devil has committed.
Nor does God take away all that he gave to his nature; but sometimes He takes, and something He leaves, so that there should be something remaining to feel pain at the loss. And this very pain is evidence of the good that was taken and the good that was left. For had good not been left, he could not feel pain for the good lost. For a sinner is worse if he rejoices in the loss of righteousness; but he who is tormented, though he may gain no good thereby, yet grieves for the loss of salvation. And since both righteousness and salvation are good, and the loss of any good is cause for grief rather than for joy (at least where there is no compensation in the form of a better good, as righteousness of soul is better than bodily health), surely it is more fitting for an unjust man to grieve in punishment than to rejoice in sin. So even as the rejoicing of a sinner because he has abandoned what is good is evidence of a bad will, so his grief in punishment, because of the good that he has lost, is evidence of a good nature. For he who mourns the lost peace of his nature does so by his possession of some remnants of that peace, by reason of which his nature is friendly to itself. Now it is right that in the last punishment the wicked and impious should weep in their torments for the loss of the good that was in their natures, being aware that he who deprived them is an altogether just God whom they scorned when he was the altogether kindly distributor of bounty.
God, then, the most wise creator and most just ordainer of all nature, who has set upon the earth as its greatest adornment the mortal human race, has bestowed on man certain good things that befit his life; to wit, temporal peace, so far as it can be enjoyed in the little span of a mortal life in terms of personal health and preservation and fellowship with one's kind, and all things necessary to safeguard or recover this peace (such as the objects that are suitably and conveniently available for our senses; light, speech, air to breathe an water to drink, and whatever befits the body, to feed and cover it, to heal and adorn it); all this under the most just condition that every mortal who rightly uses such goods, that are designed to contribute to the peace of mortals, shall receive larger and better goods, that is, the peace of immortality, and the glory and honour appropriate to it in an everlasting life spent in the enjoyment of God and of one's neighbour in union with God; while he who use the goods of this life perversely shall lose them, and shall not receive those of the everlasting life.
Peace in Love [XIX, 14]
Therefore every use of temporal things is related to the enjoyment of earthly peace in the earthly city, while in the earthly city it is related to the enjoyment of everlasting peace. Wherefore, if we were irrational animals, we should seek nothing beyond the ordered proportionment of the components of the body and the assuagement of the appetites; nothing, that is, beyond repose of the flesh and good store of pleasure, so that the peace of the body might further serve the peace of the soul. For if bodily peace be wanting, the peace of the irrational soul is also impaired, because it cannot achieve the assuagement of its appetites. But the two together serve the mutual peace of soul and body, the peace of an ordered life and health. For just as animals, by avoiding pain, show that they love bodily peace, and by pursuing pleasure in order to satisfy the wants of their appetites, show that they love peace of soul, so by their shunning death they give a sufficient indication how great is their love of the peace that harmonizes soul and body.
But because man has a rational soul, he subordinates all that he has in common with the beasts to the peace of the rational soul in order that he may exercise his mind in contemplation and may act in accordance with it, and in order that he may thus enjoy that ordered agreement of knowledge and action we called the peace of the rational soul.
It is for this end that he ought to prefer to be annoyed by no pain, moved by no desire, and dissipated by no death, namely, that he may discover some profitable knowledge and may shape his life and character in accordance with such knowledge. But lest by his very eagerness for knowledge he should fall, through the weakness of the human mind, into some fatal infection of error, he needs divine instruction that he may follow with assurance, and divine assistance that he may follow it as a freeman. And since, so long as he is in this mortal body, he wanders on alien soil far from God, he walks by faith, not by sight, and therefore he subordinates all peace, of body or of soul or of both, to that peace which exists between mortal man and the immortal God, that he may show an ordered obedience in faith under the everlasting law.
Now since the divine instructor teaches two chief precepts, love of God and love of one's neighbour, and since in them man finds three objects of love, God, himself, and his neighbour, and he who loves God does not err in loving herself, it follows that he is concerned also for his neighbour that he should love God, since he is bidden to love his neighbour as himself.
He is thus concerned for his wife, his children, his household and for other men so far as he can be; and he would wish his neighbour to be so concerned for him, should he perchance stand in need of it. Therefore he will be at peace, so far as in him lies, with all men in that human peace, or ordered agreement, of which the patter is this: first, to do harm to no man, and secondly, to help every man that he can. In the first place, then, he has the care of his own household, inasmuch as the order of nature or of human society provides him with a readier and easier access to them for seeking their interest. Wherefore the Apostle says: 'Whosoever does not provide for his own, and especially for those of his household, he denies the faith, and is worse than an infidel.'
So at this point begins domestic peace, the ordered agreement among those who dwell together, concerning command and obedience. For those who are concerned for others give commands, the husband to his wife, the parents to their children, the master to their servants; while those who are objects of concern obey; for example, the women obey their husbands, the children their parents, the servants their masters. But in the home of the just man who lives by faith and who is still a pilgrim in exile from the celestial city, even those who give commands serve whom they seem to command. For they command not through lust for rule but through dutiful concern for others, not with pride in exercising princely rule but with mercy in providing for others.
Concord in Earthly Peace [XIX, 17]
But a household of human beings whose life is not governed by faith pursues an earthly peace by means of the good things and the conveniences of this temporal life, while a household of those who live by faith looks to the everlasting blessings that are promised for the future, using like one in a strange land any earthly and temporal things, not letting them entrap him or divert him from the path that leads to God, but making them a means to brace his effort to ease the burden and by no means to aggravate the load imposed by the corruptible body, which weighs down the soul. Therefore both kinds of human groups and of households use alike the things that are necessary for this mortal life; but each has its own very different end in using them. So, too, the earthly city, that lives not by faith, seeks an earthly peace, and its end in aiming at agreement concerning command and obedience on the part of citizens is limited to a sort of merging of human wills in regard to the things that are useful for this mortal life. Whereas the heavenly city, or rather the part of it that goes its pilgrim way in this mortal life and lives by faith, needs must make use of this peace too, though only until this mortal lot which has need of it shall pass away. Therefore, so long as it leads its life in captivity, as it were, being a stranger in the earthly city, although it has already received the promise of redemption, and the gift of the spirit as a pledge of it, it does not hesitate to obey the laws of the earthly city whereby matters that minister to the support of mortal life are administered to the end since that since this mortal life is common to both, a harmony may be preserved between both cities with regard to the things that belong to it.
But because the earthly city has had certain philosophers of its own, whose doctrine is rejected by the divine teaching, and who follow their own surmise or were deceived by demons, and so believed that there are many gods to be won over to support human interests, and that different provinces belong to different responsibilities of theirs, so that the body is the province of one, the soul is another; and in the body, one governs the head, another the neck, and so forth with each of the several members; likewise in the soul, one presides over the natural intelligence, another over education, another over anger, still another over lust; and in the adjuncts of life, one god cares for flocks, other gods severally for grain, wine, oil, woods, money, navigation, wars and victories, marriage, birth, fecundity and so forth; and because the heavenly city, on the other hand, knew only one God to be worshipped and believed with faithful piety that He is to be served with that service which in Greek is called ,and should be rendered only to God, it has come to pass that the heavenly city could not have common laws of religion with the earthly city, and on this point must dissent and became a tiresome burden to those who thought differently, and must undergo their anger and hatred and persecutions, except that at length it shook the hostile intent of its adversaries with fear of its own numbers and with evidence of the ever-present divine aid.
While this heavenly city, therefore, goes its way as a stranger on earth, it summons citizens from all peoples, and gathers an alien society of all languages, caring naught what difference may be in manners, laws and institutions by which early peace is gained or maintained, abolishing and destroying nothing of the sort, nay rather preserving and following them (for however different they may be among different nations, they aim at one and the same end, earthly peace), provided that there is no hindrance to the religion that teaches the obligation to worship one most high and true God. Even the heavenly city, therefore, in its pilgrimage makes use of the earthly peace, and guards and seeks the merging of human wills in regard to the things that are useful for man's mortal nature, so far as sound piety and religion permit, and makes the earthly peace minister to the heavenly peace, which is so truly peace that it must be deemed and called the only peace, at least of a rational creature, being, as it is, the best ordered and most harmonious fellowship in the enjoyment of God and of one another in God. And when we arrive thither, there shall be no mortal life, but a life indeed; no animal body to burden the soul with its corruption, but a spiritual body that wants nothing and is subdued in every part to the will. This peace the heavenly city during its pilgrimage enjoys by faith, and by this faith it lives justly when it makes the attainment of that peace the goal of every good action in which it engages for the service of God and one's neighbour; for the life of a city is certainly a social life.