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.

(参考: Apocalypse Revealed 435)

2183. 'He took butter and milk, and the young bull which he had made ready' means all those things so joined together. This becomes clear from the meaning of 'butter', 'milk', and 'the young bull', which are dealt with in the next paragraph. The subject in the verses previous to this has been the providing of the Lord's Rational with that which is celestial and that which is spiritual derived from this, meant by 'the meal of fine flour made into cakes', 2176, 2177, and also with the celestial-natural, meant by 'the young bull', 2180. The same things are now expressed by other words - by 'butter', 'milk', and 'a young bull', which mean all those same things when they have been joined together.

[2] But one is scarcely able to describe these matters to the ordinary mind because the majority do not know that every person possesses an internal, a rational, and a natural, and that these three are quite distinct and separate from one another, so distinct in fact that one can be at variance with another. That is to say, the rational, which is called the rational man, can be at variance with the natural, which is the natural man; indeed the rational man is able to see and perceive evil that is in the natural, and if it is a genuine rational, is able to correct it, see 1904. Before these two have been joined together man is unable to be whole or to experience the serenity of peace, since the one is in conflict with the other. For the angels present with a person govern his rational, while the evil spirits present with him govern his natural - and this gives rise to conflict.

[3] If in this conflict the rational prevails, the natural is placed in subjection, and the man is thus endowed with conscience; but if the natural prevails, he is not able to receive any conscience at all. If the rational prevails, his natural becomes as though it too was rational; but if the natural prevails, the rational becomes as though it too was natural. In addition, if the rational prevails, angels draw nearer to that person, implanting within him charity, a celestial quality which comes through the angels from the Lord; and at the same time the evil spirits move some distance away from him. But if the natural prevails, the angels move further away, that is, more towards his interiors, and the evil spirits draw nearer to the rational, constantly attack it, and fill the lower parts of his mind with forms of hatred, revenge, deceit, and the like. If the rational prevails, the man enters into the serenity of peace, and in the next life into the peace of heaven; but if the natural prevails, though during his lifetime he seems to experience serenity, he enters in the next life into the unrest and torment of hell.

[4] From these considerations one may know the nature of a person's state so far as his rational and so far as his natural are concerned. There is nothing else that can bring him blessing and happiness except the conformity of his natural to the rational when both are joined together. This is achieved solely by means of charity; and charity originates wholly in the Lord.