In Genesis 4:22, 'Tubal-Cain, an instructor of every artificer in brass and iron,' as in Genesis 4:22, signifies the doctrine of natural good and truth. Tubal-Cain is called an instructor of every artificer, and not a father, like Jabal and Jubal, because celestial and spiritual, or internal things, did not exist before. This is why the term 'father' is applied in the case of Jabal and Jubal, the first existence of these internal things. As natural or external things existed before, but were now applied to internal things, Tubal-Cain is not called a father, but an instructor of the artificer. (Arcana Coelestia 421)