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)

1799. 'Behold, a son of my house is my heir' means that in the Lord's kingdom there would be only that which is external. This is clear from the meaning in the internal sense of 'an heir' and of 'inheriting'. 'Becoming an heir' or inheriting means eternal life in the Lord's kingdom. All who are in the Lord's kingdom are heirs, for the source of the life in them is the Lord's life, which is the life of mutual love, and for that reason they are called 'sons'. The Lord's sons or heirs consist of all who have His life in them, for it is from Him that their life comes, and it is from Him that they have been born, that is, regenerated. Those born of another are that other's heirs; and so it is with all who are being regenerated by the Lord, for in that case they are receiving the life that is the Lord's.

[2] In the Lord's kingdom there are those who are external, those who are more interior, and those who are internal. Good spirits who dwell in the first heaven are external, angelic spirits who dwell in the second heaven are more interior, and angels who dwell in the third heaven are internal. Those who are external are not as close to or near the Lord as those who are more interior, and these in turn are not so close or near as those who are internal. Out of Divine love, or mercy, the Lord wills to have everyone near to Himself, so that they do not stand outside, that is, in the first heaven. His will is that they should dwell in the third heaven, and if possible not merely with Him but abiding in Him. Such is the nature of Divine or the Lord's love. But since at that time none but external things existed with the Church, He complained of this in the words that occur here - 'Behold, a son of my house is my heir' - by which is meant that in His kingdom there would thus be only that which is external. But comfort followed, and a promise of internal things, as described in the verses that follow next. What the external aspect of the Church is has been stated already in 1083, 1098, 1100, 1151, 1153.

[3] By itself doctrine does not constitute the external aspect of the Church, still less the internal, as stated above. Nor on the Lord's part is it its teachings that make one Church distinct and separate from another, but its life in accordance with those teachings, all of which, as long as they present what is true, regard charity as their basic principle. What else does doctrine do but teach men the kind of people they ought to be?

[4] In the Christian world it is their doctrines that cause Churches to be distinct and separate, and because of these they call themselves Roman Catholics, Lutherans, Calvinists or the Reformed, and Evangelicals, among other names. It is solely by reason of their doctrines that they are called by these names. This situation would never exist if they were to make love to the Lord and charity towards the neighbour the chief thing of faith. In this case their doctrinal differences would be no more than shades of opinion concerning the mysteries of faith which truly Christian people would leave to individual conscience, and in their hearts would say that a person is truly a Christian when he lives as a Christian, that is, as the Lord teaches. If this were so all the different Churches would become one, and all the disagreements which stem from doctrine alone would disappear. Indeed the hatred one man holds against another would be dispelled in an instant, and the Lord's kingdom on earth would come.

[5] The Ancient Church which existed immediately after the Flood, though scattered among many kingdoms, was of this nature. That is to say, people differed much from one another in matters of doctrine, but for all that, they made charity the chief thing. Also they regarded worship, not from the standpoint of doctrinal teachings which are matters of faith, but from that of charity which is a matter of life. This is what is meant by 'they all had one lip and their words were one', Genesis 11:1, regarding which see 1285.

2228. 'And in him all the nations of the earth will be blessed' means that from Him all who have charity will be saved. This is clear from the meaning of 'being blessed' as being endowed with all goods that have a heavenly origin, dealt with in 981, 1096, 1420, 1422. People who are endowed with goods from a heavenly origin, that is, with celestial goods and spiritual goods, which have been referred to immediately above in 2227, are also endowed with eternal salvation, that is, they are saved. 'All nations of the earth' is used to mean in the internal sense those with whom the goods exist that flow from love and charity, as is clear from the meaning of 'nation' as good, dealt with in 1159, 1258-1260, 1416, 1849. That 'all the nations of the earth' does not mean all people throughout the whole world may become clear to anyone, for there are so many among them who are not saved. Only those who have charity, that is, who have acquired the life of charity, are saved.

[2] So that the whole matter of the salvation of people after they have died does not remain hidden from anyone, let a brief discussion of it follow here. There are many who declare that man is saved through faith, or as they say, if he merely has faith. But the majority of such people do not know what faith is. Some imagine that it is mere thought; some that it is the acknowledgement of something which ought to be believed; others that it is the entire doctrine of faith, which ought to be believed; and others something different again. Thus in their mere knowledge of what faith is they are mistaken, and as a consequence they are mistaken as to what it is that saves a person. Faith however is not mere thought; nor is it the acknowledgement of something that ought to be believed; nor is it a knowledge of all that constitutes the doctrine of faith. Nobody can be saved by such thought, acknowledgement, or knowledge that cannot send down roots any deeper than thought. Thought does not save anyone, but the life which he acquires to himself in the world through the cognitions of faith. Such life remains, but all thought that is not in keeping with his life dies away, even to the point of becoming none at all. In heaven that which brings people into association with one another is their lives, not thoughts that are not related in any way to a person's life. Thoughts which are unrelated to a person's life are spurious and are totally rejected.

[3] In general there are two kinds of life, the first being the life of hell, the second that of heaven. The life of hell is derived from all those intentions, thoughts, and deeds that flow from self-love, consequently from hatred against the neighbour. The life of heaven is derived from all those intentions, thoughts, and deeds that belong to love towards the neighbour. This heavenly life is that to which all things called faith have regard and is acquired by means of all things of faith. From this it becomes clear what faith is, namely that it is charity, for all things that are said to be part of the doctrine of faith lead to charity. Charity embraces them all and from charity they are all derived. After the life of the body, the soul is such as its love is.