366. That they should slay one another, signifies the falsification or extinction of truths. This is evident from the signification of "slaying," as meaning the extinction of truths; for "to slay" in the Word signifies to slay spiritually, that is, to slay the spiritual part of a man or his soul, which is to extinguish truths. It also means to falsify, because when truths are falsified they are also extinguished; for falsification produces a different understanding of truths, and truth is true to everyone according to his understanding of it; for the love and principle that rule in man draw and apply all things to themselves, even truths themselves; consequently when the love is evil, or the principle is false, then truths are infected with the evil of the love or the falsity of the principle, and thus are extinguished. This, therefore, is what is here signified by "they should slay one another." That this takes place when there is no good with man, and especially when there is no good in the doctrine of his church, is evident from the preceding words, where it is said, "When he had opened the second seal there went forth a red horse; and to him that sat upon him it was given to take peace from the earth;" which signifies a second state of the church when the understanding of the Word is destroyed in respect to good, which is the source of dissensions in the church (of which see above, n. 361, 364, 365).

[2] That the understanding of the Word, or what is the same, the understanding of the truth, is destroyed when there is no good with man, that is, when there is no love to the Lord and charity towards the neighbor, may be seen above n. 365; for good with man, or what is the same, love with him, is the fire of his life, and truth with him, or the faith of truth, is the light therefrom; consequently such as the good is, or such as the love is in man, such is truth, or such the faith of truth in him. From this it can be seen that when evil or an evil love is with man there can be no truth or faith of truth with him; for the light that goes forth from such fire is the light that those have who are in hell, which is a fatuous light like the light from burning coals, which light, when light from heaven flows in, is turned into mere thick darkness. Such also is the light that with the evil, when they reason against the things of the church, is called natural light [lumen].

[3] That they would falsify and thereby extinguish truths is meant also by the Lord's words in Matthew:

Jesus said to the disciples, The brother shall deliver up the brother, the father the son; children shall rise up against parents, and cause them to be put to death (Matthew 10:21).

And in Luke:

Ye shall be delivered up by parents, and brethren, and kinsfolk, and friends; and some of you shall they cause to be put to death (Luke 21:16).

"Parents," "brethren," "children," ["kinsfolk, "] and "friends," do not mean here parents, brethren, children, kinsfolk, friends, nor do "disciples" mean disciples, but the goods and truths of the church, also evils and falsities; it is also meant that evils would extinguish goods and falsities truths. (That such is the signification of these words, see Arcana Coelestia 10490.)

634. It is extremely difficult however to state intelligibly what the understanding of truth and the will for good are, properly speaking. The reason is that everything man thinks he ascribes to the understanding because he calls it so, and everything he desires he ascribes to the will because he calls it so. And it is even more difficult to state what they are in an intelligible way because the majority nowadays are also unaware that what belongs to the understanding is distinct and separate from what belongs to the will; for when they think something they say that they will it, and when they will something they say that they think it. Their speaking in this way is thus one reason for the difficulty. And a further reason why it is difficult to grasp the matter is that such people are engrossed solely in bodily interests, that is, their life consists in things of a more external nature.

[2] For these same reasons people are also unaware of the fact that with everybody there exists something interior, something more interior still, and indeed something inmost, and that the bodily and sensory part of a person is the most external. Desires and things of the memory are interior, affections and rational concepts more interior still, while the will for good and the understanding of truth are the inmost. Nothing could possibly be more distinct and separate than these are from one another, yet a bodily-minded man sees no difference at all, and so confuses them all with one another. This is the reason why he believes that when his physical body dies, everything else will die as well, when in reality only at that point does he start to live, and to do so indeed through his own interior things which are arranged in consecutive order. Unless man's interior things were distinct and separate in this way and arranged consecutively, men could not possibly be spirits, angelic spirits, or angels in the next life, all of whom differ in this way from one another according to things that are interior. Consequently the three heavens are very distinct and separate from one another. From all these considerations it now becomes clear to some extent what the understanding of truth and the will for good are, properly speaking, and that they are attributable only to the celestial man, or angels of the third heaven.