Certainly whatever is bad in its increase is bad in its birth.
Now grief and all other perturbations are doubtless baneful in their progress, and have, therefore, no small share of evil at the beginning; for they go on of themselves when once they depart from reason, for every weakness is self-indulgent, and indiscreetly launches out, and does not know where to stop.

So that it makes no difference whether you approve of moderate perturbations of mind, or of moderate injustice, moderate cowardice, and moderate intemperance; for whoever prescribes bounds to vice admits a part of it, which, as it is odious of itself, becomes the more so as it stands on slippery ground, and, being once set forward, glides on headlong, and cannot by any means be stopped.
XIX.

Why should I say more?
Why should I add that the Peripatetics say that these perturbations, which we insist upon it should be extirpated, are not only natural, but were given to men by nature for a good purpose?
They usually talk in this manner.

In the first place, they say much in praise of anger; they call it the whetstone of courage, and they say that angry men exert themselves most against an enemy or against a bad citizen: that those reasons are of little weight which are the motives of men who think thus, as--it is a just war; it becomes us to fight for our laws, our liberties, our country: they will allow no force to these arguments unless our courage is warmed by anger .-- Nor do they confine their argument to warriors; but their opinion is that no one can issue any rigid commands without some bitterness and anger.
In short, they have no notion of an orator either accusing or even defending a client without he is spurred on by anger.

And though this anger should not be real, still they think his words and gestures ought to wear the appearance of it, so that the action of the orator may excite the anger of his hearer.