94. 6. A love for the opposite sex is a love of the external or natural man, and is therefore common to every animal. Everybody is born carnal and becomes more and more inwardly natural, and to the extent that he loves intelligence he becomes rational, and afterwards, if he loves wisdom, he becomes spiritual. (We will say later, in no. 130, what that wisdom is, by which a person becomes spiritual.)

Now as a person advances from knowledge to intelligence, and from this to wisdom, his mind also changes its form accordingly, for it opens up more and more and becomes more closely connected with heaven and through heaven with the Lord. Consequently the person becomes a greater lover of truth and more devoted to goodness of life.

If a person stops, therefore, at the first stage in his progress towards wisdom, the form of his mind remains natural, and it receives the inflowing of the universal atmosphere - the atmosphere of the marriage between good and truth - in just the same way as it is received by the lower members of the animal kingdom called beasts and birds. And because these are merely natural, the person becomes like them, and consequently he feels a love for the opposite sex in the same way they do.

This is what we mean by the statement that a love for the opposite sex is a love of the external or natural man, and is therefore common to every animal.

162. 6. This union takes place gradually from the first days of marriage, and in people who are in a state of truly conjugial love, it becomes deeper and deeper to eternity. The first heat in marriage does not join two people together, because it draws its character from a love for the opposite sex, which is a love belonging to the body and on that account to the spirit. And whatever is in the spirit as a result of the body does not last long. But love that is in the body as a result of the spirit does last. Love belonging to the spirit, and to the body as a result of the spirit, is insinuated into the souls and minds of married partners together with friendship and mutual trust. When friendship and mutual trust join together with the first love in marriage, conjugial love results, which opens the partners' hearts and inspires in them the sweet enjoyments of love, and this more and more deeply as friendship and trust are added to the original love, and as that original love enters into this friendship and trust and they into it.