Blessed are the peacemakers: for they shall be called the children of God.
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Augustine of Hippo
It is the perfection of peace, where nothing offers opposition; and the children of God are peacemakers, because nothing resists God, and surely children ought to have the likeness of their father. Now, they are peacemakers in themselves who, by bringing in order all the motions of their soul, and subjecting them to reason— i.e. to the mind and spirit— and by having their carnal lusts thoroughly subdued, become a kingdom of God: in which all things are so arranged, that that which is chief and pre-eminent in man rules without resistance over the other elements, which are common to us with the beasts; and that very element which is pre-eminent in man, i.e. mind and reason, is brought under subjection to something better still, which is the truth itself, the only-begotten Son of God. For a man is not able to rule over things which are inferior, unless he subjects himself to what is superior. And this is the peace which is given on earth to men of goodwill; this the life of the fully developed and perfect wise man. From a kingdom of this sort brought to a condition of thorough peace and order, the prince of this world is cast out, who rules where there is perversity and disorder. When this peace has been inwardly established and confirmed, whatever persecutions he who has been cast out shall stir up from without, he only increases the glory which is according to God; being unable to shake anything in that edifice, but by the failure of his machinations making it to be known with how great strength it has been built from within outwardly.