Arcana Coelestia #2623
2623. 'A son' means the Divine Rational. This is clear from the meaning of 'a son'. In the internal sense of the Word 'a son' means truth, 489, 491, 533; and because truth is the principal element in the rational, 2072, 2189, 'a son' also means the rational. But here the Divine Rational is meant in which the principal element is good. 'Isaac' too, to whom 'a son' refers, represents this good, as will be shown further on.
Arcana Coelestia #533
533. Since nothing further is mentioned about Lamech apart from the fact that be beget sons and daughters, who are the conceptions and births of such a Church, there is no need to pause any longer over him. What these births, or sons and daughters, were, becomes clear from the Church, for the character of a Church determines that of its offspring. Both those Churches called Methuselah and Lamech breathed their last just before the flood.