From the “Ethics.”

LOVE is a certain attuning of the appetite to that which is apprehended as suitable, while hatred is a sort of dissonance of the appetite from that which is apprehended as unsuitable and hurtful. But as everything suitable, as such, bears the stamp of good, so everything unsuitable, as such, bears the stamp of evil; and therefore as good is the object of love, so evil is the object of hatred.

  Being, as being, has nothing in it of variance, but only of concord, because all things agree in being: but being, inasmuch as it is this determinate being, is at variance with some other determinate being; and in this way one being is hateful to another, and is evil, not in itself, but in relation to another.

  As things are apprehended as good, which are not really good, so things are apprehended as evil which are not really evil; hence it happens sometimes that neither hatred of evil nor love of good is good.

  In every case we should consider what agrees with a thing before we consider what disagrees with it; for to disagree with a thing is to mar or hinder what agrees with it. Hence love must be prior to hatred; and nothing can be hated except what is contrary to some agreeable thing that is loved. And thus all hatred is caused by love.

  Love and hatred are contraries when they both turn on the same object; but when they are about contrary objects, they are not contraries, but consequences one of the other: for it is on one and the same ground that a thing is loved and its contrary hated; and thus the love of one thing is the cause of its contrary being hated.

  Is it possible for any one to hate himself?

  Properly speaking, it is impossible for any one to hate himself. For naturally everything seeks good, and cannot seek for itself anything except in the light of good. But to love any one is to wish him good. Hence a man needs must love himself, and cannot possibly hate himself, properly speaking. Accidentally, however, it comes about that a man hates himself, and this in two ways: in one way in regard of the good which he wishes for himself, for it happens sometimes that what is sought as being in a certain respect good is simply evil; and in this way one accidentally wishes evil to himself, which is to hate. The same may happen in another way in regard of the being to whom he wishes good, namely, himself. Every being is that especially which is the leading element in its composition: hence the State is said to do what the King does, as though the King were the whole State. It is clear then that man is especially the mind of man. But it happens that some men take themselves to be that especially which they are in their bodily and sensitive nature. Hence they love themselves according to that which they take themselves to be, but hate that which they really are, in that they will things contrary to reason. And in both of these ways “he that loveth iniquity, hateth” not only “his own soul,” but also himself.