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. We can say the same of the church as we have of heaven, since the church is the Lord's heaven on earth. It also has many components, and yet each is called a church and is a church to the extent that the qualities of love and faith rule within it. In it, the Lord forms a single whole out of the varied elements, and therefore makes a single church out of many churches. ¹

Much the same can be said of the individual member of the church as has been said about the church in general, namely that the church is within and not outside, and that anyone is a church in whom the Lord is present in the qualities of love and faith. ²

Much the same can be said of the individual who has the church within as has been said about the angel who has heaven within, that such an individual is a church in least form as the angel is a heaven in least form. Even more, we can say that the individual who has the church within is a heaven just as much as an angel is, for we have been created to enter heaven and become angels. So anyone who has the quality of goodness from the Lord is an angel-person. ³

It is worth noting what we have in common with angels and what we possess that they lack. We have in common with angels the fact that our deeper levels are formed in the image of heaven and that we also become images of heaven to the extent that we participate in the qualities of love and faith. What we have that angels lack is that our more outward levels are formed in the image of this world; and that to the extent that we are engaged in what is good, the world within us is subordinated to heaven and serves it; ⁴ and that then the Lord is present with us on both levels as he is in his heaven. He is actually present on both levels in his divine order, for God is order. ⁵

Footnotes:

6057. Before anything can be said about the influx and operation of the soul into the body, a proper knowledge is required of the truth that the internal man has been created so as to conform to an image of heaven, and the external man to an image of the world, so much so that the internal man is the smallest form heaven can take, and the external man is the smallest the world can take and is thus the microcosm. The fact that the external man is an image of the world can be seen from his external or physical senses. The ear has been made to conform to the whole nature of the modification of air, and the lungs to the whole nature of air-pressure. So too with the surface-areas of the body, which are held in shape by the pressure of air all around them. The eye has been made to conform to the whole nature of the ether and light; the tongue to the perception of particles dissolved and suspended in fluids, and at the same time along with the lungs, trachea, larynx, glottis, jaws, and lips to conform to the power of using air in varying ways to produce articulated sounds or words, and musical sounds too. The nostrils have been made to conform to the perception of particles suspended in the atmosphere, and touch, a sense which is distributed over the whole of the body, to the perception of changes in the condition of the air, that is to say, whether it is cold or hot, as well as the perception of the nature of fluids and the weights of objects. (The internal organs, which the air surrounding the body cannot enter, are held together and kept in shape by a purer kind of air, called ether.) This is not to mention all the deeply hidden aspects of the natural world that have been inscribed on and apply themselves to the body, such as all the secrets of mechanics, physics, chemistry, and optics. All this goes to prove that the entire natural order was drawn on so that the external side of the human being might be created in conformity with it, which was why the ancients named the human being the microcosm.

[2] Now just as the external man has been created so as to conform to an image of everything in the world, so the internal man has been created so as to conform to an image of everything in heaven, that is, an image of the celestial and spiritual qualities that come from the Lord, from which heaven is formed and in which it consists. The celestial qualities there are all the aspects of love to the Lord and charity towards the neighbour, and the spiritual qualities are all the aspects of faith. They are intrinsically so great and of such a nature that no tongue can possibly declare even a millionth of them. The truth that the internal man has been made so as to conform to an image of all those qualities is plain to see in the angels. When they appear before a person's internal sight, as they have appeared before mine, their presence alone stirs feelings to the depths of his being. For love to the Lord and charity towards the neighbour pour out of them and into the onlooker; and what is radiated by that love and charity, namely rays of faith, shines out of them and stirs one's affections. This has served to show, as well as other proofs, that because the internal man has been created to be an angel, the internal man is the smallest form heaven can take.

[3] From all this it now becomes clear that within the human being the spiritual world has been joined to the natural world. As a result, in the case of the human being, the spiritual world flows into the natural world in so vital a way that a person can discern it if he merely stops to pay attention to it. This also shows what the interaction of the soul with the body is, that strictly speaking it is a communication of the spiritual realities of heaven with the natural things of the world, a communication which is effected by one flowing into the other, yet depends on the way the two have been joined together. This communication effected through an inflowing which depends on the way the two have been joined together is unknown at the present day, for the reason that every single thing is attributed to natural forces and there is no knowledge of what is spiritual, which at the present day is so remote that when people give it any thought it seems to be non-existent.