They whose minds are least sensitive to calamity, and whose hands are most quick to meet it, are the greatest men and the greatest communities. - Thucydides

But as the power of Hellas grew, and the acquisition of wealth became more an objective, the revenues of the states increasing, tyrannies were established almost everywhere...

If you give way, you will instantly have to meet some greater demand, as having been frightened into obedience in the first instance; while a firm refusal will make them clearly understand that they must treat you more as equals.

Our opinion of the gods and our knowledge of men lead us to conclude that it is a general and necessary law of nature to rule whatever one can. This is not a law that we made ourselves, nor were we the first to act upon it when it was made. We found it already in existence, and we shall leave it to exist for ever among those who come after us. We are merely acting in accordance with it, and we know that you or anybody else with the same power as ours would be acting in precisely the same way.
Goodwill shown by the party that is asking for help does not mean security for the prospective ally. What is looked for is a positive preponderance of power in action.