On Hate by Baruch Spinoza

Hatred is an inclination to ward off from us that which has caused us some harm. Now it is to be remarked that we perform our actions in two ways, namely, either with or without passion. With passion, as is commonly seen in the [conduct of] masters towards their servants who have done something amiss. Without passion, as is related of Socrates, who, when he was compelled to chastise his slave for [the latter's own] good, never did so when he felt that he was enraged against his slave.

Now that we see that our actions are performed by us either with or without passion, we think that it is clear that those things which hinder or have hindered us can be removed, when necessary, without any perturbation on our part. And so, which is better: that we should flee from the things with aversion and hatred, or that, with the strength of reason, we should (for we think it possible) endure them without loss of temper? First of all, it is certain that when we do what we have to do without passion, then no evil can result therefrom. And, since there is no mean between good and evil, we see that, as it is bad to do anything in a passion, so it must be good to act without it.