423. Tubal-cain is called 'a teacher of every craftsman' but not 'a father' as Jabal and Jubal have been. The reason is that celestial and spiritual, or internal, things did not exist previously. Those two are called fathers because those things first existed at that point, whereas natural or external things did exist previously, though now allied to internal things. Therefore he is not called 'a father' but 'a teacher of craftsmen'.

54. Doctrine not only makes the Word understandable, but also to shine, so to speak, and that is because the Word is not understood apart from doctrine and is like a lampstand without any light, as we showed above. Doctrine is what makes the Word understandable, therefore, so as to be like a lampstand with its lamp lit. A person then sees much more than he saw before, and also understands what he had not understood before. Dark and conflicting passages he either does not see and passes on by, or sees and explains them so as to be in harmony with the doctrine.

The Word’s being viewed in the light of doctrine, and moreover explained in accordance with it, is something experience in the Christian world attests. For the Protestant Reformed all see the Word in the light of their doctrine and explain the Word in accordance with it. Roman Catholics likewise see the Word in the light of their doctrine and explain it in accordance with that doctrine. Indeed, Jews do the same. Consequently falsities are seen in the light of a false doctrine, and truths in the light of a true doctrine.

It is apparent, therefore, that a true doctrine is like a lamp shining in darkness, and like a signpost pointing the way.

Doctrine, however, must not only be drawn from the Word’s literal sense, but it must also be verified by it. For if not verified by it, doctrinal truth has the appearance of having only man’s intelligence in it, and not the Lord’s Divine wisdom, and in that case doctrine would be like a house in the air and not on the ground, thus one without its foundation.