'Dan' means those who are guided by truth but not as yet by good. 'Will judge his people, as one of the tribes of Israel' means that it is one of the truths in general which the tribes of Israel represent. 'Dan will be a serpent on the road' means their reasoning regarding truth, since good does not as yet lead them. 'A darting serpent on the path' means reasoning from truth regarding good. 'Biting the horse's heels' means false notions received from the lowest natural level. 'And its rider will fall backwards' means a receding from [truth]. 'I wait for Your salvation, O Jehovah' means unless the Lord brings them aid.