358. (1) Viewed in itself, zeal is, so to speak, the fire of love set ablaze. One cannot know what jealousness is unless one knows what zeal is; for jealousness is the zeal of conjugial love. Zeal is, so to speak, the fire of love set ablaze, because zeal is an expression of love, and love is spiritual warmth, which in its origin is a kind of fire. As regards the first point, that zeal is an expression of love - this people know. When they speak of being zealous and acting from zeal they mean nothing else than an intensity of love. But because it does not appear as love when it manifests itself, but as antagonistic and hostile - being militant and combative against one who does injury to the love, therefore it may also be called the defender and protector of love. For it is the nature of all love to erupt into indignation and anger, even into rage, whenever it is dislodged from its delights. So it is that if love is interfered with, especially a governing one, there results a disturbance of the mind. And if that interference does injury, it becomes a white-hot fury. It can be seen from this that zeal is not the highest degree of love, but that it is love set ablaze. When one person's love finds a corresponding love in another, they are like two confederates; but when one person's love rises up against another's love, they become as enemies. The reason is that love is the very being of a person's life. Consequently, anyone who attacks another's love, attacks his very life; and this results in a state of white-hot fury against the attacker, like the state of anyone who encounters another trying to kill him. Every love is capable of such fury, even the most peaceable, as is plainly evident from the behavior of hens, geese, and birds of every kind and the way they fearlessly rise up against and fly at those who injure their young or make off with their food. People know that some animals are prone to anger, and wild animals to rage, if their cubs are attacked or their prey taken from them. Love is said to blaze like fire, because love is nothing but spiritual warmth, arising from the fire of the angelic sun, which is pure love. That love is warmth, as though from a fire, is clearly apparent from the warmth of living bodies, whose warmth is from no other source than the love in them. So, too, human beings grow warm and are set on fire in the measure that their loves are aroused. It is apparent from this that zeal is, so to speak, the fire of love set ablaze.