The concept of a "church" in the Writings is both complex and beautifully organic, linked with teachings on the nature of the Lord and the resulting nature of mankind.

The Writings say that the Lord, in His essence - His actual substance - is perfect, infinite love, a love that powered creation, that is the ultimate source of reality, and that sustains reality constantly. That love is expressed in form as perfect, infinite wisdom, which gave form to creation and gives form to reality.

Deep stuff! You can read more about that elsewhere, but what matters here is that all of creation, from the smallest elements to the whole of the universe, reflects that same structure. It's present in nature itself, powered by the heat (love) and light (wisdom) of the sun. It's present in the essential forms of life, with plants (which are rooted; which change little; which are unfeeling; which are powered by light) representing elements of wisdom and animals (warm, feeling, mobile, ever-changing, powered by heat) representing forms of love. It's present in the near-universal division into male (wisdom) and female (love) aspects of plants and animals alike.

That structure is also in each of us. In common language we might call these our hearts and our minds - what we want and what we think. The Writings commonly talk of them as good (love; what we want in our hearts) and truth (wisdom; what we know in our minds) or as will (heart) and understanding (mind). Not only do these elements define us, they are also key to our spiritual fates. We can use them to accept the Lord's love, come into the good of life and ultimately go to heaven. We can also use them to reject the Lord's love and trot off to hell.

And there are further layers. The Writings say that all human societies are in human form, with functions analogous to the human body. This is true from small groups like families to large companies to entire nations and ultimately to both the entire human race in this world and the entirety of heaven in the next.

Among the most important human societies are, naturally, churches. Since the concept of a "church" is based on the human form, though, churches as referred to in the Writings can take many forms. At one end of the scale, any one person who has true ideas of right and wrong and lives by them is a church himself or herself. At the other end of the scale, all those in the whole world who believe in love of the neighbor – and act from that belief – collectively make up one church.

Many other varieties lie between those two extremes, but most references to "church" in the Writings mean the community of those who have the Word, know the Lord, and follow His commandments. These people have access to the best possible truth and deepest possible understanding about the nature of the Lord and what He wants from us.

Such a church plays a vital role: The Lord works through it to get ideas about being good into people's minds and the desire to be good into the inner recesses of their hearts, reaching far beyond that church itself to touch everyone in the world. In fact, the Writings say there is in essence a marriage between the Lord and the church, with the church in the role of the bride and wife, producing true ideas and good desires the way a wife produces children.

To protect this function, the Lord has made sure that throughout history (and a good bit of prehistory) there has always been a church filling this role.

The first of these was the Most Ancient Church, represented by Adam; it was inspired by love of the Lord. The second was the Ancient Church, represented by Noah; it was inspired by love of the neighbor and knowledge of the Lord. The third was the Israelitish Church, which had no interior love of good but preserved ideas of the Lord. The fourth was the primitive Christian church, which had a new, more direct understanding based on the Lord's teachings. The fifth, according to the Writings, is to be based on the deeper understanding offered through the Writings and their explanations of the Bible.

There is much more that could be said, but we'll just emphasize one other point:

We as individuals are who we are based on what we love, not what we know. We will go to heaven or to hell based on what we love, not what we know. Knowing, thinking and seeking truth are important things, but their purpose is to shape, guide and serve our loves; love is ultimately what matters. The Writings make it abundantly and repeatedly clear that it is the same with churches: They are ultimately based on love, not knowledge, on their determination to serve the neighbor, not their external forms of worship. And if churches share that common purpose of serving the neighbor then they are in essence one, with doctrinal variations being of little consequence.

(References: Apocalypse Revealed 533; Arcana Coelestia 407, 768, 1799 [3-4], 2048, 2853 [2-3], 2910, 2982, 3310, 3773, 3963 [2], 4292, 4672, 4723, 5826 [2-3], 6637, 6648, 8152, 9256 [4-5], 9276 [2]; Conjugial Love 116; Heaven and Hell 57; The Word 8; The Doctrine of the New Jerusalem Regarding the Sacred Scripture 99, 104)

57. What has been said of heaven can be said of the Church, for the Church is the Lord's heaven on earth. There are also many Churches, and yet any one of them is called the Church and indeed is a Church, so far as the good of love and of faith rules there. There again, the Lord out of diversity makes a unity, thus, one Church out of many Churches. ¹ The same, too, can be said of the man of the Church in particular as is said of the Church in general, namely, that the Church is within a man and not outside him, and that every man in whom the Lord is present in the good of love and of faith is a Church. ² Again, the same can be said of a man in whom is the Church as of an angel in whom is heaven, namely, that he is a Church in least form as an angel is heaven in least form, and furthermore, that a man in whom is the Church, equally with an angel, is a heaven. For man has been created that he may come into heaven and become an angel. Consequently, he who has good from the Lord is an angel-man. ³ It may be mentioned what a man has in common with an angel and what he has in addition to what angels have. A man has this in common with an angel, that his interiors are equally conformed to the image of heaven and that he, too, in so far as he is in the good of love and faith, may become an image of heaven. In addition to what angels have, a man has these things, that his exteriors have been formed according to the image of the world, that so far as he is in good, the world with him is subordinated to heaven and serves heaven, ⁴ and that then the Lord is present with him in both worlds, just as if he were in his heaven. For the Lord is in His Divine order in both worlds, since God is order. ⁵

Footnotes:

4279. The explanations given so far to these two verses present what they contain in the highest sense and in the internal sense. But in the lower sense they have a different meaning. There the essential nature of Jacob and his future descendants is the subject. Because the Word originates in the Lord and comes down from Him by way of heaven to man its nature is therefore such that it is Divine in every detail. And as it has come down from the Lord so it goes up, that is, is raised up to Him, returning by way of the heavens. It is well known that there are three heavens, and that the inmost is termed the third heaven, that the middle one is called the second heaven, while the lowest is referred to as the first heaven. Consequently since it goes up by the same path as it comes down the Word as it exists in the Lord is Divine, celestial as it exists in the third heaven since that heaven is the celestial heaven, spiritual as it exists in the second heaven since that heaven is the spiritual heaven, but celestial-natural and spiritual-natural as it exists in the first heaven, which is also given the names celestial-natural and spiritual-natural. As it exists in the Church with man however, the Word in the sense of the letter is natural, that is, worldly and earthly.

[2] From this one may see the nature of the Word and what happens to it when a person reads it with a holy mind, that is, one in whom good and truth are present. For when he reads it, it is seen by him as something existing in this world or as a historical document, but which nevertheless is inwardly holy. But in the first heaven it is seen as something celestial-natural and spiritual-natural, which however is inwardly Divine. In the second heaven it is spiritual, and in the third celestial; and in the Lord it is Divine. The sense in the Word varies according to whatever heaven it may be. The highest sense of the Word, whose subject is the Lord, exists for the inmost or third heaven; the internal sense, whose subject is the Lord's kingdom, exists for the middle or second heaven; the lower sense, in which the internal sense is narrowed down to the nation referred to there, exists for the lower or first heaven. But the lowest or literal sense exists for man while he is still living in the world. Yet man's nature is such that the more interior sense, and also the internal and highest sense, can be communicated to him. For man has communication with the three heavens; indeed he is created on the pattern of the three heavens, so much so that when love to the Lord and charity towards the neighbour constitute his life he is heaven in miniature. Consequently such a person has the Lord's kingdom within him, as the Lord Himself teaches in Luke,

Behold, the kingdom of God is within you. Luke 17:21.

[3] These things have been stated so that people may know that the Word contains not only a highest sense and an internal sense but also a lower sense, and that in this sense, that is to say, in the lower, the internal sense is narrowed down to the nation referred to there; and when this is done that sense is plain to see from the train of thought. At present it is self-evident that the man's wrestling with Jacob and the disjointing and displacing of his thigh also has reference to Jacob and his descendants. That being so, let these same words be explained according to that sense. In what follows below this sense will be termed the INTERNAL HISTORICAL SENSE. It will be called this for the added reason that it is quite usual for this sense to be represented from time to time in the first heaven as something animate and taking visible form, as also I have been allowed to see several times. See the explanation given already in the latter part of 4272.