[2] The reason no doctrine of faith from the rational exists is that the rational is immersed in the appearances of good and truth, and such appearances are not truths in themselves, as shown already in 2053, 2196, 2203, 2209. What is more, the rational bases itself on illusions, which are the product of external sensory impressions confirmed by facts which introduce haziness into those appearances of truth. The rational for the most part is merely human, as also becomes clear from its birth. This then is why nothing of the doctrine of faith can even be started, let alone be built up from it. Such doctrine must stem from the Lord's Divine itself and His Divine Human. This is the origin of it, so much so indeed that the Lord is doctrine itself. It is for this reason also that in the Word He is called the Word, the truth, the light, the way, and the door. Furthermore - and this is an arcanum - all doctrine is derived from Divine Good and Divine Truth and possesses the heavenly marriage within it. Doctrine which does not possess this within it is not the genuine doctrine of faith. Consequently every detail of the Word, the source of doctrine, holds the image of a marriage within it, see 683, 793, 801.

[3] It does indeed seem in the literal or external sense of the Word as though the doctrine of faith possessed much from the rational and indeed from the natural. But the reason for this is that the Word exists for the sake of man, for whom it has been adapted in this way. Nevertheless in itself the Word is spiritual from a celestial origin, that is, it is derived from Divine Truth joined to Divine Good. The fact that doctrine would be brought to ruin if the rational were consulted as regards the contents of that doctrine will be illustrated by examples in what follows.