That marriage is heaven and that adultery is hell cannot be better seen than from considering their origin.  The origin of true marriage love is the Lord’s love for the church; and this is why the Lord is called in the Word a “Bridegroom” and a “Husband,” and the church a “bride” and a “wife.”  It is from this marriage that the church is a church in general and in particular.  The church in particular is a man in whom the church is.  From this it is clear that the Lord’s conjunction with a man of the church is the very origin of true marriage love; and how that conjunction can be the origin shall be told.

The Lord’s conjunction with a man of the church is a conjunction of good and truth; good is from the Lord, and truth is a man, and from this is the conjunction that is called the heavenly marriage, and from that marriage true marriage love exists between the married pair that are in such conjunction with the Lord.

From this it is now evident that true marriage love is from the Lord alone, and exists in those who are in the conjunction of good and truth from the Lord.  As this conjunction is reciprocal it is said by the Lord that

   They are in Him, and He in them (John xiv. 20).

This conjunction or this marriage was thus established from creation.  The man was created to be an understanding of truth, and the woman to be an affection for good; and thus the man to be a truth, and the woman to be a good.  When understanding of truth which is in the man makes one with the affection for good which is in the woman, there is a conjunction of the two minds into one.  This conjunction is the spiritual marriage from which marriage love descends.  For when two minds are so conjoined as to be one mind there is love between them; and when this love, which is the love of spiritual marriage, descends into the body it becomes the love of natural marriage.  That this is so anyone can clearly perceive if he will.  A married pair who interiorly or in respect to their minds love each other mutually and reciprocally also love each other mutually and reciprocally in respect to their bodies.  It is well known that all love descends into the body from an affection of the mind, and that apart from such an origin no love exists.

Since then the origin of marriage love is the marriage of good and truth, which marriage in its essence is heaven, it is clear that the origin of the love of adultery is a marriage of evil and falsity, which in its essence is hell.  Heaven is a marriage because all who are in the heavens are in a marriage of good and truth; and hell is adultery because all who are in the hells are in a marriage of evil and falsity.  From this it follows that marriage and adultery are as opposite as heaven and hell are. (A.E., n. 983.)