I answer that, From the very fact that a man desires a certain thing it follows that he desires to obtain what he desires, and, in consequence, to remove whatever may be an obstacle to his obtaining it. Now a man may be hindered from obtaining the good he desires, by a contrary desire either of his own or of some other, and both are removed by peace, as stated above. For as we stated above, there is no peace when a man concords with another man counter to what he would prefer. Consequently men seek by means of war to break this concord, because it is a defective peace, in order that they may obtain peace, where nothing is contrary to their will. Hence all wars are waged that men may find a more perfect peace than that which they had heretofore.
Peace gives calm and unity to the appetite.
Now just as the appetite may tend to what is good simply, or to what is good apparently, so too, peace may be either true or apparent. There can be no true peace except where the appetite is directed to what is truly good, since every evil, though it may appear good in a way, so as to calm the appetite in some respect, has, nevertheless many defects, which cause the appetite to remain restless and disturbed. Hence true peace is only in good men and about good things. One is perfect peace. It consists in the perfect enjoyment of the sovereign good, and unites all one's desires by giving them rest in one object.