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)

3773. 'And they would put the stone back in its place over the mouth of the well' means that it was closed up for the time being. This is clear from what has been stated about the stone over the mouth of the well, in 3769, 3771. With regard to these considerations, namely that the Word was uncovered for the Churches and after that closed up, the position is that in the beginning, when any Church is established, the Word is in that initial period closed up to them but later on, through the Lord's provision, is opened up. And from there people learn that all doctrine is based on these two commandments, that the Lord is to be loved above everything else, and the neighbour as themselves. When these two commandments are the end in view the Word is in that case opened up, for all the Law and all the Prophets, that is, the whole of the Word, hangs on them, as does everything from them, and so everything has reference to them. And being in that case governed by the primary teachings concerning truth and good people receive light in each particular thing they see in the Word. For the Lord is present with them at that time by means of angels and is teaching them even though they are not directly aware of it, and is also guiding them into the life of truth and good.

[2] This may also be seen from the consideration that in their infancy all Churches have been such, and have from love worshipped the Lord, and have from the heart loved the neighbour. But in course of time Churches have moved away from these two commandments, and have turned away from good flowing from love and charity towards those things called matters of faith, and so have turned away from life towards doctrine. And to the extent this happens the Word is closed up. These are the factors meant in the internal sense by the words, 'Behold, a well in the field, and behold, three droves of a flock there, lying nearby it; for out of that well they watered the droves; and there was a large stone over the mouth of the well. And all the droves would be gathered there; and they would roll the stone from over the mouth of the well and water the flock; and they would put the stone back in its place over the mouth of the well'.

10648. 'And they go whoring after their gods' means from which falsities of evil arise. This is clear from the meaning of 'whoring after the gods of the nations' as being linked to falsities of evil; for being linked together unlawfully is meant by 'whoring', and falsities of evil by 'the gods of the nations'. For the meaning of 'gods' as falsities, see 4402(end), 4544, 7873, 8867, and for that of 'nations' as evils, above in 10638. The expression 'from which falsities of evil arise' is used because from evil all kinds of falsity come forth. Falsities however which do not arise from evil are indeed falsities in the outward form they take, but they are not inwardly so. For falsities can exist with someone who leads a good life; but they have good interiorly present in them which causes the evil of the falsity to be removed. Consequently that falsity does not appear before angels as falsity but as a sort of truth; for angels look at the inner features of faith, not the outward aspects of it. This is why everyone, whatever their religion, even gentiles who possess no truths from the Word, can be saved, provided that they have regarded leading a good life as their end in view, and the religious teachings they have received as the means to that end, see 2589-2604.

[2] 'Whoring' is spoken of frequently in the Word. An unlawful joining to truth is meant by this, and an unlawful joining to good by 'committing adultery', so that 'whoring' means the falsification of truth, and 'committing adultery' the adulteration of good. The falsification of truth takes place in the following three ways,

1. If a person leads an evil life while acknowledging truths received through religious teachings, for the truths then have evil inside them, and evil falsifies truth. It does so because evil dispels from truths what is heavenly and Divine, and introduces what is hellish, as a consequence of which falsification takes place.

[3] 2. If a person first accepts the truths in religious teachings and afterwards assents to the falsity of another set of teachings, which happens solely in the case of those who lead an evil life, because evil has an appetite for falsity and freely takes hold of it as the truth.

3. If a person who is leading an evil life and adopting falsities as his religious teachings takes hold of truths belonging to another set of teachings, he too falsifies truths, because he does not acknowledge truths for their own sake, only for the sake of earning some gain, important position, or reputation.

[4] In the Word all these kinds of falsification are called acts of whoredom and prostitution, because a lawful joining together, which is that of goodness and truth, is meant by a marriage, see 2727-2759, so that instances of an unlawful joining together are meant by acts of whoredom. The truth of this may be recognized from a large number of places in the Word, of which let just these two be brought forward here:

In Ezekiel,

O Jerusalem, you committed whoredom because of your renown, and poured out your acts of whoredom on every passer-by. You took some of your garments and made for yourself high places variously coloured, and on them committed whoredom. For your adornment you took vessels made of My gold and of My silver, which I had given you, and made for yourself figures of the male, and committed whoredom with them. You took your sons and your daughters, whom you had borne to Me, and sacrificed them to them. Were your acts of whoredom a small matter? You committed whoredom with the sons of Egypt, your neighbours, great in flesh, and multiplied your whoredom to provoke Me to anger. You committed whoredom with the sons of Asshur, and you committed whoredom with them and were not satisfied. And you multiplied your whoredom, even as far as the trading land of Chaldea. Ezekiel 16:15-17, 20, 26, 28-29ff.

And in the same prophet,

Two women, the daughters of one mother, committed whoredom in Egypt. In their youth they committed whoredom. Oholah is Samaria, and Oholibah is Jerusalem. Oholah committed whoredom under Me and doted on her lovers, on the Assyrians her neighbours. She bestowed her acts of whoredom on them. Her acts of whoredom brought from Egypt she did not give up, for they had lain with her in her youth. Oholibah corrupted her love more than she, and multiplied her acts of whoredom above her sister's acts of whoredom; she doted on the sons of Asshur. She added to her acts of whoredom and saw the images of the Chaldeans. As soon as her eyes saw them she desired them. The sons of Babel came to her, into her love-bed. Ezekiel 23:2-5, 7-8, 11-12, 14, 16ff.

Further examples of the same thing occur in many other places, which may be seen, together with explanations of them as well as of the two quoted here, in 2466, 8904.