In Genesis 49:12, "teeth whiter than milk" signify the Celestial Spiritual [milk] in the Lord's Natural [teeth], where Judah is here representing the Lord. (Arcana Coelestia 2184-2185).

In Psalms 3:7; 37:12, 58:6; Matthew 8:12, teeth signify the lowest natural things in man: in the genuine sense, their truths, in the opposite sense, their falsities. So the gnashing of teeth signifies the collision of falsities with truths. (Arcana Coelestia 4424[3])

In Exodus 21:27, this signifies truth in the natural, here the ultimate, which is the sensuous. (Arcana Coelestia 9062)

The tooth signifies the corporeal proprium, which is the lowest degree of man. (Arcana Coelestia 10283[12])

'Teeth,' as in Genesis 49:12, in the genuine sense, signify the natural level of life. Any hard part of the body, like bones and cartilage, corresponds to the truths and goods of the lowest natural level. 'Teeth' signify the outer edges of the life of the natural self, or the sensory level. There is a natural sensory will, and a natural sensory understanding. When the sensory levels are separated from the interior of the mind, their supposed truths are really mere falsities, and do violence to truths and destroy them. This situation appears in many passages, because sensory people do not see any truth in its own light, but engage in reasoning and altercations about everything... These altercations are heard in the hells as the gnashing of teeth. Viewed in itself, this is the collision of falsity and truth. This is the meaning of 'gnashing of teeth' in Matthew 8:12, 13:42, 50, 22:13, 24:51, 25:30, and Luke 13:28.

(Referências: Apocalypse Revealed 435)

6222. 'And he took his two sons with him, Manasseh and Ephraim' means the Church's will and the Church's understanding, born from the internal. This is clear from the representation of 'Manasseh' as the new will in the natural and its essential nature, dealt with in 5354 (end); and from the representation of 'Ephraim' as the new understanding in the natural and its essential nature, dealt with in 5354. The birth of the two from the internal is meant by the fact that they were the sons of Joseph, who represents the internal celestial, 5869, 5877.

[2] What the Church's understanding is and what its will is must be stated. The Church's understanding consists in perceiving from the Word what the truth of faith is and what the good of charity is. As is well known, the literal sense of the Word is by nature such that a person can use that sense to support any opinion at all that he may adopt. The reason for this is that ideas appearing in the literal sense of the Word serve as general vessels to receive truths, though not until they have actually received truths does the real nature of those vessels reveal itself as if through transparency. Thus those ideas form merely a general impression which a person must gain first in order that he may aptly receive particular aspects and specific details. This fact - that the literal sense of the Word is by nature such that a person can use that sense to support any opinion at all that he may adopt - is clearly evident from the great number of heresies that have existed in the Church, and still exist in it. Adherents of each heresy find support for it in the literal sense of the Word, support which enables them to believe fully that it is the truth, which means that if they were to hear the actual truth from heaven they would receive nothing at all of it.

[3] The reason why they would not receive it is that they do not share in the understanding that the Church possesses; for that understanding exists when people read the Word, assiduously take one statement together with another, and by doing so see what they ought to believe and what they ought to do. Such understanding comes only to those who receive light from the Lord, whom the Christian world also calls 'the enlightened'. That enlightenment does not come to any but the kind of people who have the desire to know truths, not for the sake of reputation and glory but for the sake of life and service. That same enlightenment is received by a person in his understanding, for the understanding is the receiver of light. This is clearly evident from the fact that people who have little understanding cannot by any means see such things from the Word but have faith in those who they think are the enlightened. Furthermore it should be recognized that those who have been regenerated receive from the Lord an understanding which is capable of being enlightened; and it is the light of heaven coming from the Lord that flows into the understanding and gives it light, for the understanding receives its light, its sight, and consequently its perception from no other source.

[4] But this understanding which is being called the Church's understanding is more internal than an understanding based merely on factual knowledge, for it consists in a discernment that a thing is true not because factual evidence and philosophical deductions dictate it but because the Word in its spiritual sense does so. For example, people who possess the Church's understanding can perceive clearly that in every single part the Word teaches that love to the Lord and charity towards the neighbour are the essential qualities of the Church, that a person's life continues after death, and that his life arises out of his loves. They can also perceive that faith separated from charity is not faith, that faith contributes nothing to eternal life except in the measure that the good of love to the Lord and the good of charity towards the neighbour are linked to it, and that faith and charity must therefore be joined together so that spiritual life may exist. People with an enlightened understanding can perceive quite clearly that these things are true; but those without it can by no means see that they are.

[5] It is thought that the people with an understanding in things of the Church are those who know how to substantiate extensively the opinions or teachings of their Church, to the point of convincing others that they are true, and who know how to refute numerous heresies in a masterly way. But this is not what is meant by the Church's understanding, for substantiating opinions is not a characteristic of the understanding but of mental ability at a sensory level, which sometimes comes to exist in very wicked people; indeed those without any beliefs at all, also those who are steeped in actual falsities, can have that ability. Nothing comes more easily to both these kinds of people than to substantiate whatever idea they like, so thoroughly that they convince the simple. But before substantiating any opinion the Church's understanding engages in seeing and perceiving whether it is true or not, and in substantiating it only after that.

[6] This understanding is what is represented by 'Ephraim'. But the Church's good, which is represented by 'Manasseh', is the good of charity, which the Lord instills into a member of the Church through the truths of faith. For these truths together with the good of charity are what flow into the understanding and give it light, and also enable the understanding and the will to constitute one mind. The truth that both these - the understanding and the will - are born from the internal may be seen from what was stated and shown previously; for the whole affection for goodness and truth, the affection through which enlightenment comes, flows in from no other origin, thus is born from no other origin than the internal; that is, it comes from the Lord through the internal.