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:

5608. 'Even our young children' means aspects even more internal. This is clear from the meaning of 'young children' as things that are more internal, 5604. The reason more internal things are meant by 'young children' and also by 'boys (or older children)' is that innocence is meant by both these, and innocence is something inmost. The situation in heaven is that the inmost or third heaven consists of those in whom innocence dwells because they are moved by love to the Lord. For the Lord is Innocence itself, so that those who are there because they are moved by love to Him have innocence dwelling within them. And although they are the wisest ones of all in heaven, they look to others there like young children. For this reason, as well as for the reason that innocence dwells in young children, innocence is meant in the Word by 'young children'.

[2] Since innocence is the inmost virtue of heaven, innocence must exist inwardly with all who are in heaven. It is like entities of a consecutive nature in relation to those that come into being simultaneously, that is, entities existing separated from one another in distinct degrees in relation to ones that come into being from these. For everything that comes into being simultaneously has its origin in entities of a consecutive nature. When simultaneous things take rise from consecutive ones they position themselves in the same order as that in which they existed initially, separated into distinct degrees. Take, by way of illustration, end, cause, and effect. These exist consecutively, distinct and separate from one another. When they come into being simultaneously they position themselves in the same order; that is to say, the end takes up the inmost position, the cause the position after this, and the effect the one that comes last. The effect comes into being simultaneously with the others; for unless the cause is present within the effect, and the end within the cause, no effect exists. If you remove the cause from the effect you destroy the effect, and all the more so if you remove the end from the cause. The end enables the cause to be a cause, and the cause enables the effect to be an effect.

[3] The same is so in the spiritual world; just as end, cause, and effect are distinct and separate from one another, so in the spiritual world are love to the Lord, charity towards the neighbour, and the deeds of charity. When these three are made one, that is, when they come forth simultaneously, the first has to be within the second, and the second within the third. Likewise within the deeds of charity: unless charity flowing from affection or the heart is present inwardly in those deeds, they are not the deeds of charity; and unless love to the Lord is present inwardly in charity it is not charity. If therefore you take away the inward substance, the outward form perishes; for the outward form is brought into being and kept in being by the loves existing in order within it. The same is so with innocence. It makes one with love to the Lord. Unless innocence is present inwardly in charity it is not charity. Consequently unless charity that has innocence within it is present inwardly in the deeds of charity, they are not the deeds of charity. This being so, innocence must be present inwardly with all who are in heaven.

[4] The truth of this, as well as the fact that innocence is meant by 'young children', is clear in Mark,

Jesus said to the disciples, Let the young children come to Me and do not hinder them; for of such is the kingdom of God. Truly I say to you, Whoever has not received the kingdom of God like a young child will not enter into it. Taking them up therefore in His arms, He laid His hand upon them, and blessed them. Mark 10:14-16; Luke 18:15-17; Matthew 18:3

Here 'the young children' clearly means innocence, for the reason that innocence resides with young children, and for the reason that in heaven forms of innocence are seen as young children. No one can enter heaven unless he possesses some measure of innocence, see 4797.

[5] What is more, young children allow themselves to be governed by angels who are filled with innocence; children do not act independently, the way adults govern personal behaviour by the exercise of their own judgement and will. The fact that young children allow themselves to be governed by angels is clear from the Lord's words in Matthew,

See that you do not despise any one of these little ones, for I say to you that their angels in heaven always see the face of My Father. Matthew 18:10.

No one can see God's face except by virtue of having innocence.

[6] Innocence is meant by 'young children' in the following places as well:

In Matthew,

Out of the mouth of young children and sucklings You have perfected praise. Matthew 21:16; Psalms 8:1.

In the same gospel,

You have hidden these things from the wise and intelligent and have revealed them to young children. Matthew 11:25; Luke 10:21.

The innocence meant by 'young children' is true wisdom; for genuine innocence dwells within wisdom, 2305, 2306, 4797. This explains why it is said that 'out of the mouth of young children and sucklings You have perfected praise', and also that such matters 'have been revealed to young children'.

[7] In Isaiah,

The young cow and the bear will feed; their young will lie down together. And a suckling will play over the viper's hole. Isaiah 11:7-8.

This refers to the Lord's kingdom, specifically to the state of peace and innocence there. 'Suckling' stands for innocence. The impossibility that any evil can befall those in whom innocence is present is meant by 'the suckling will play over the viper's hole' - 'vipers' being utterly deceitful persons. This chapter in Isaiah refers quite explicitly to the Lord. In Joel,

Blow the trumpet in Zion; gather the people, sanctify the congregation, assemble the elders, gather the young children and those sucking at the breast. Joel 2:15-16.

The elders' stands for the wise ones, 'the young children and those sucking at the breast' for the innocent ones.

[8] In the following places too 'young children' is used to mean innocence, but here innocence that has been destroyed: In Jeremiah,

Why are you committing great evil against your own souls, to cut off from you man and woman, young child and suckling from the midst of Judah, so that I leave you no remnant? Jeremiah 44:7.

In the same prophet,

Lift up to Him your hands for the soul of your young children who faint through famine at the head of every street. Lamentations 2:19.

In Ezekiel,

Go through Jerusalem and strike; do not let your eye spare, and show no pity. [Utterly slay] old man, young man, virgin, and young child. Ezekiel 9:5-6

In Micah,

The women of My people you cast out from each one's pleasant house; from her young children you take away My honour for ever. Micah 2:9.

[9] As regards the innocence present in young children, this is solely external, not internal; and because it is not internal it cannot be linked to any wisdom and exist together with it. But the innocence in angels, especially in those of the third heaven, is internal, and so exists joined to wisdom, 2305, 2306, 3494, 4563, 4797. Furthermore the human being has been created in such a way that when he grows old and becomes like a young child, the innocence of wisdom links itself to the innocence of ignorance that had been his when he was a young child, and in this condition, as a true young child, he passes over into the next life.