This is the same as with sexual love; if it becomes active before marriage, it is called fornication. Everyone is by birth bodily, and becomes sensual and then natural; then by stages he becomes rational and, so long as he does not stop at this point, spiritual. The reason for such a development is to form levels to support the higher stages, like foundations for a palace. The lowest level which supports the superstructure can be compared with the ground, in which, when it has been prepared, fine seeds are planted.

[2] As regards sexual love in particular, it too is at first bodily, for its starts from the flesh. It then becomes sensual, for the five senses are delighted by sharing in it. Later it becomes natural and similar to the form it takes in animals, which is a roving sexual love. But since man is by birth destined to become spiritual, this love becomes rational-natural and from this spiritual, and finally spiritual-natural. Then once the love has become spiritual it influences and acts on rational love, and through this on sensual love, and through this finally on this love in the body and the flesh. Since the flesh is its lowest level, it acts upon it spiritually, and at the same time rationally and sensually. When a person is thinking about it, it influences and acts on him successively; but at the lowest level, its effects are all felt at once.

[3] Fornication belongs to the natural man, because it is the immediate development from natural sexual love. It may be a rational natural love, but not a spiritual one, because sexual love cannot become spiritual until it becomes conjugial. Sexual love changes from natural to spiritual when a person abandons roving lust and commits himself to one partner, with whose soul he unites his own.