The strong do what they can and the weak suffer what they must

Quotes from Thudydides in The Peloponnesian War.

To hear this history rehearsed, for that there be inserted in it no fables, shall be perhaps not delightful. But he that desires to look into the truth of things done, and which (according to the condition of humanity) may be done again, or at least their like, shall find enough herein to make him think it profitable. And it is compiled rather for an everlasting possession than to be rehearsed for a prize.

[snip]

But, the bravest are surely those who have the clearest vision of what is before them, glory and danger alike, and yet notwithstanding, go out to meet it.

[snip]

Right, as the world goes, is only in question between equals in power, while the strong do what they can and the weak suffer what they must.

[snip]

The cause of all these evils was the lust for power arising from greed and ambition; and from these passions proceeded the violence of parties once engaged in contention.

[snip]

The State that separates its scholars from its warriors, will have its thinking done by cowards, and its fighting by fools.