That marriage and adultery are opposites has already been shewn in the chapter concerning their opposition; and the quantity and quality of their opposition cannot be learnt but from their intermediates, of which concubinage is one; but as there are two kinds of concubinage, which are to be carefully distinguished, therefore this section, like the foregoing, shall be arranged into its distinct parts as follows; I. There are two kinds of concubinage, which differ exceedingly from each other, the one conjointly with a wife, the other apart from a wife. II. Concubinage conjointly with a wife, is altogether unlawful for Christians, and detestable. III. That it is polygamy which has been condemned, and is to be condemned, by the Christian world. IV. It is an adultery whereby the conjugial principle, which is the most precious jewel of the Christian life, is destroyed. V. Concubinage apart from a wife, when it is engaged in from causes legitimate, just, and truly excusatory, is not unlawful. VI. The legitimate causes of this concubinage are the legitimate causes of divorce, while the wife is nevertheless retained at home. VII. The just causes of this concubinage are the just causes of reparation from the bed. VIII. Of the excusatory causes of this concubinage some are real and some not. IX. The really excusatory causes are such as are grounded in what is just. X. The excusatory causes which are not real are such as are not grounded in what is just, although in the appearance of what is just. XI. Those who from causes legitimate, just, and really excusatory, are engaged in this concubinage, may at the same time be principled in conjugial love. XII. While this concubinage continues, actual connection with a wife is not allowable. We proceed to an explanation of each article.

463.  I. THERE ARE TWO KINDS OF CONCUBINAGE, WHICH DIFFER EXCEEDINGLY FROM EACH OTHER, THE ONE CONJOINTLY WITH A WIFE, THE OTHER APART FROM A WIFE.  That there are two kinds of concubinage, which differ exceedingly from each other, and that the one kind consists in taking a substituted partner to the bed and living conjointly and at the same time with her and with a wife; and that the other kind is when, after a legitimate and just separation from a wife, a man engages a woman in her stead as a bed-fellow; also that these two kinds of concubinage differ as much from each other as dirty linen from clean, may be seen by those who take a clear and distinct view of things, but not by those whose view of things is confused and indistinct:  yea, it may be seen by those who are in conjugial love, but not by those who are in the love of adultery.  The latter are in obscurity respecting all the derivations of the love of the sex, whereas the former are enlightened respecting them:  nevertheless, those who are in adultery, can see those derivations and their distinctions, not indeed in and from themselves, but from others