The History of the Grecian War (1.77.3-1.77.5)

For they that have the power to compel need not at all to go to law. And yet these men having been used to converse with us upon equal terms, if they lose anything which they think they should not, either by sentence or by the power of our government, they are not thankful for the much they retain, but take in worse part the little they forego than if at first, laying law aside, we had openly taken their goods by violence. For in this kind also they themselves cannot deny but the weaker must give way to the stronger.

And men, it seems, are more passionate for injustice than for violence. For that, coming as from an equal, seemeth rapine, and the other, because from one stronger, but necessity.

Therefore, when they suffered worse things under the Medes' dominion, they bore it, but think ours to be rigorous. And good reason, for to men in subjection the present is ever the worst estate.