Portion of a passage from Arcana Coelestia ~ Emanuel Swedenborg
By "brethren" in the internal sense are signified those who are in similar good and truth, that is, in a similar affection of good and truth. For in the other life all are consociated in accordance with the affections, and those who are consociated constitute a brotherhood. Not that they call themselves brethren, but that they are brethren by conjunction.In the other life it is good and truth that produce that which on earth is called relationship by blood and by marriage; and therefore there is a correspondence between the two things; for regarded in themselves goods and truths acknowledge no other father than the Lord, for they are from Him alone. Hence all who are in goods and truths are in brotherhood; but still there are degrees of relationship according to the quality of the goods and truths. These degrees are signified in the Word by "brothers," "sisters," "sons-in-law," "daughters-in-law," "grandsons," "granddaughters," and by other family names.
On earth they are so named with reference to a common parentage, however they may differ in regard to affections; but this brotherhood or relationship is dissipated in the other life, and unless they have been in similar good on earth, they there come into other brotherhoods. At first indeed they for the most part come together, but in a short time are separated; for in that world it is not wealth that keeps men together, but as just said, affections, the quality of which is then manifest as in clear day, and also the kind of affection which one has had toward another.
And as these are manifest, and as everyone's affection draws him to his society, those who have been of a discordant disposition are dissociated; and all the brotherhood and friendship which had been of the external man are obliterated on both sides, and that which is of the internal man remains.
(Arcana Coelestia 4121)