In Genesis 25:3, this signifies knowledge of celestial things or people who uphold the doctrine of charity. (Arcana Coelestia 3240[3])

In Ezekiel 27:15, this signifies knowledges of lower celestial matters in rituals. (Arcana Coelestia 1172)

In Jeremiah 49:8, this signifies rituals lacking internal worship or adoration of the Lord from the heart. (Arcana Coelestia 1172) Dedan, in Jeremiah 49:8, signifies rituals wherein there is no internal worship. Dedan (Genesis 10) signifies the knowledges of celestial things of an inferior order, such as those in ritual observances.

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.