In Psalm 80:2, they signify the three constituents of the spiritual church, namely its intelligence of truth; its truth of good; and its voluntary or goodwill in act. (Arcana Coelestia 3909[3, 8, 13])

Cities of the mountain and cities of the plain (Jeremiah 33:13) signify doctrines of charity and faith.

(Referencat: Arcana Coelestia 2418)