Selection from True Christian Religion ~ Emanuel Swedenborg
Faith in its beginning in man is natural, and that as man draws near to the Lord it becomes spiritual; so also with charity. But no one has known, as yet, the distinction that exists between natural and spiritual faith and charity. This great arcanum must therefore be disclosed.There are two worlds - a natural and a spiritual; and in each world there is a sun, and from each sun heat and light go forth; but the heat and light from the sun of the spiritual world have life within them; this life is from the Lord who is the midst of that sun; while the heat and light from the sun of the natural world have nothing of life in them; they simply serve the former heat and light as receptacles for the conveying of these to man, as instrumental causes always subserve their principal causes. It must be understood, therefore, that all things spiritual are from the heat and light of the sun of the spiritual world. These are spiritual because they contain in them spirit and life; while all things natural are from the heat and light of the sun of the natural world, which viewed in themselves are without spirit and life.
Since then faith is a matter of light, and charity of heat, it is plain that so far as a man is in the heat and light that go forth from the sun of the spiritual world, he is in spiritual faith and charity; while so far as he is in the light and heat that go forth from the sun of the natural world, he is in natural faith and charity. Evidently, therefore, as spiritual light is inwardly in natural light as in its receptacle or casket, and spiritual heat in like manner within natural heat, so also is spiritual faith inwardly in natural faith, and spiritual charity inwardly in natural charity; and this is effected in the degree that man advances from the natural to the spiritual world; and this he does so far as he believes in the Lord who is light itself, the way, the truth, and the life, as He Himself teaches.
This being so, it is clear that when man is in spiritual faith, he is also in natural faith. For as just said, spiritual faith is inwardly in natural faith; and as faith is a matter of light, it follows that by that implanting of spiritual faith man's natural becomes, as it were, transparent, and according to the nature of its conjunction with charity, beautifully colored. This is because charity is ruddy and faith shining white; charity is ruddy from the flame of spiritual fire, and faith shining white from the splendor of the light therefrom.
The contrary happens when the spiritual is not inwardly in the natural, but the natural inwardly in the spiritual; which is the case with men who reject faith and charity. With such the internal of their mind, in which they are when left to their own thoughts, is infernal, and they think from hell, although they do not know it; while the external of the mind of such, from which they converse with their companions in the world, is in a manner spiritual, but it is filled full of such unclean things as are in hell; consequently they are in hell, for compared with the former class they are in an inverted state.
When it is thus known that the spiritual is inwardly in the natural in those who are in faith in the Lord, and at the same time in charity toward the neighbor, and consequently the natural in them is transparent, it follows that to the same extent man is wise in spiritual things, and therefrom in natural things; for when he thinks about or hears or reads anything, he sees interiorly within himself whether it is the truth or not. This he perceives from the Lord, from whom spiritual light and heat flow into the higher sphere of his understanding.
So far as faith and charity in man become spiritual, he is withdrawn from his own, and ceases to look to himself or to reward or remuneration, and looks solely to the delight in perceiving the truths of faith and doing the good works of love; and so far as this spirituality increases, that delight becomes blessedness. From this is man's salvation, which is called eternal life. This state of man may be compared with the most beautiful and charming things in the world, and in the Word is compared with them, as for instance, with fruitful trees and the gardens in which they are, with flowery fields, with precious stones, with delicacies, with nuptials and their festivities and rejoicings.
But when the reverse is the case, that is to say, when the natural is inwardly in the spiritual, and consequently the man in his internals is a devil, but in his externals is like an angel, he may be compared to a dead man in a coffin of costly and gilded wood; he may also be compared to a skeleton adorned with clothing like a man, and drawn about in a magnificent carriage; or to a corpse in a sepulchre built like the temple of Diana; and his internal may be pictured even as a nest of serpents in a cavern, and his external as butterflies whose wings are tinted with all kinds of colors, but which nevertheless stick foul eggs to the leaves of useful trees, and so destroy the fruit. Or the internal of such may be compared to a hawk, and their external to a dove, and their faith and charity to a hawk pursuing a fleeing dove, which at length he wearies and then darts upon and devours.
(True Christian Religion 360 - 361)