Tauhidul Islam

“men ought either to be well treated or crushed, because they can avenge themselves of lighter injuries, of more serious ones they cannot; therefore the injury that is to be done to a man ought to be of such a kind that one does not stand in fear of revenge. But in maintaining armed men there in place of colonies one spends much more, having to consume on the garrison all the income from the state, so that the acquisition turns into a loss, and many more are exasperated, because the whole state is injured; through the shifting of the garrison up and down all become acquainted with hardship, and all become hostile, and they are enemies who, whilst beaten on their own ground, are yet able to do hurt. For every reason, therefore, such guards are as useless as a colony is useful. Again, the prince who holds a country differing in the above respects ought to make himself the head and defender of his less powerful neighbours, and to weaken the more powerful amongst them, taking care that no foreigner as powerful as himself shall, by any accident, get a footing there; for it will always happen that such a one will be introduced by those who are discontented, either through excess of ambition or through fear, as one has seen already. The Romans were brought into Greece by the Aetolians; and in every other country where they obtained a footing they were brought in by the inhabitants.”
― Niccolò Machiavelli, The Prince