Arcana Coelestia #1065
1065. That 'these three were the sons of Noah' means these three kinds of doctrines which Churches in general possess has been stated just above. There are indeed countless less universal types of doctrines, but no further universal types exist. People who do not acknowledge charity, or faith, or external worship, are not part of any Church and are not therefore included since the Church is the subject here.
Gathered to his people
In Genesis 25:8, this signifies that all people in the same truth meet and are together in the next world.