In the ancient and Jewish churches, 'songs' were prophesies about the Lord, especially His coming in the world, subjugation of evil spirits, and liberation of the faithful from their assaults. 'Heavenly songs' are voiced affections or affections expressed and modified by sounds. As thoughts are expressed by conversation, so affections are expressed by songs. From the balance and flow of the variations, angels perceive the object of the affection.

(Reference: Conjugial Love 55)

1155. 'The sons of Javan' means others again with whom there existed external worship derived from the worship existing with the nation Javan. This in like manner becomes clear in the Prophets where they are named in connection with real things and mean nothing other than those things. The reason the sons of Gomer and the sons of Javan are named, but not the rest of the seven mentioned in verse 2, is that the sons of the one have reference to the branch of spiritual things, and the sons of the other to the branch of celestial things. The fact that 'the sons of Gomer' has reference to the branch of spiritual things is clear from the places in the Prophets quoted just above, while the fact that 'the sons of Javan' has reference to the branch of celestial things will be evident from what follows. The branch of spiritual things differs from that of celestial through this - that spiritual have regard to truths of faith but celestial to the goods of faith which are the expressions of charity. Although the world is totally ignorant of these differences they are nevertheless very well known in heaven, not only indeed as regards general but also as regards specific differences. In heaven not the smallest difference exists which is not distinct and separate within a perfect ordering. The world knows only of the existence of forms of worship, and the fact that these vary from one another. And even then it knows only of differences in externals. In heaven however the very differences themselves which are countless are plain to see, and indeed the internal nature of them.