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)

2049. 'From every son who is a foreigner and not of your seed' means those outside the Church. This is clear from the meaning of 'son who is a foreigner' as those who are not born inside the Church and so are not governed by goods and truths of faith because they have no knowledge of them. 'Sons who are foreigners' also means people whose worship is external, dealt with in 1097, though in that context people inside the Church are the subject. Here however, the subject being the Lord's Church in its widest extent, 'sons who are foreigners' means those who, like gentiles, are not born inside the Church. Gentiles outside the Church can possess truths, but not the truths of faith. Their truths, like the Ten Commandments, are that parents should be honoured; that people should not murder, steal, commit adultery, or covet the things that belong to others; and also that they should worship God. Truths of faith consist however of all doctrinal teachings concerning eternal life, the Lord's kingdom, and the Lord. Such teachings cannot be known by gentiles because they do not possess the Word.

[2] These are the people who are meant by 'sons who are foreigners and not of your seed' but who are to be circumcised, that is to be purified. From this it is evident that they are just as much capable of being purified as those inside the Church, which purification was represented by being circumcised. They are purified when they cast aside filthy loves and live among one another in charity, for in their case truths have a part to play in their lives because charity and all truths go together, though such truths belong to the first of the two types mentioned above. When these truths play a part in their lives they then absorb the truths of faith with ease, if not during this life then in the next, because truths of faith are the interior truths of charity. Indeed at that point there is nothing they desire more than to be introduced into the interior truths of charity. Interior truths of charity are what constitute the Lord's kingdom. Regarding these, see 932, 1032, 1059, 1327, 1328, 1366.

[3] In the next life mere knowledge of the cognitions of faith is of no value at all, for the worst people, even those in hell, can have such knowledge, sometimes a better knowledge than others have. Leading a life in accordance with those cognitions is what matters, for all cognitions have life as their end in view. If life was not the reason for learning them they would have no use, apart from enabling people to discuss them and as a result to be considered learned in the world, to be raised to positions of importance, and to enhance reputation and wealth. From this it is clear that a life in keeping with the cognitions of faith is nothing other than the life of charity. Indeed love to the Lord and love towards the neighbour constitute the Law and the Prophets, that is, the doctrine of faith in its entirety together with all the cognitions of it, as is plain to anyone from the Lord's words in Matthew 22:35-40, and Mark 12:28-35.

[4] Matters of doctrine, or cognitions of faith, are nevertheless absolutely vital for the formation of the life of charity; it cannot be formed without them. This is the life which saves a person after death. The life of faith never exists without the life of charity, for without charity the life of faith is impossible. People in whom the life of love and charity dwells have the Lord's life within them. Nobody can be joined to Him by means of any other life. From this it is also clear that the truths of faith cannot possibly be acknowledged as truths - that is, no acknowledgement of what they are saying is possible - other than outwardly or with the lips, if they are not implanted within charity, since inwardly or at heart they are denied. For as has been stated, all truths of faith have charity as their end in view, and if charity is not present within them then inwardly they are rejected. The nature of the things that are interior is plain to see when those that are exterior are taken away, as is done in the next life, namely that they are utterly contrary to all the truths of faith. No people can possibly receive the life of charity, or mutual love, in the next life, when they have had none in this life; but their life as it has been with them in the world remains with them after death. Indeed they are averse to and hate mutual love. When merely approaching a community where the life that belongs to mutual love exists they quiver and shake, and experience torment.

[5] Although people such as these are born inside the Church, they are called 'sons who are foreigners, uncircumcised in heart and uncircumcised in the flesh' who are not to be allowed into the sanctuary, that is, into the Lord's kingdom. They are also meant in Ezekiel,

No son who is a foreigner, uncircumcised in heart and uncircumcised in flesh, shall enter the sanctuary. Ezekiel 44:7, 9.

And in the same prophet,

Whom have you thus become like in glory and in greatness among the trees of Eden? You will be made to go down with the trees of Eden into the nether world; you will lie in the midst of the uncircumcised with those slain by the sword. Ezekiel 31:18.

This refers to Pharaoh who means types of knowledge in general, 1164, 1165, 1186, 1462. 'The trees of Eden' with which they were to go down into the nether world also means types of knowledge, but knowledge of the cognitions of faith. From this it is now evident what 'one uncircumcised' means in the internal sense, namely one in whom filthy loves and the life belonging to these are present.

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'.