"As with Gladness Men of Old"

While transcribing the lyrics for "As with Gladness Men of Old," I found an interesting connection between the text and the tune to which it's sung ("Dix").

The beginning of the fifth verse describes how the New Jerusalem will have no need of the sun because it has the light of the glory of God (Revelation 21:23):  "In the heav'nly country bright / Need they no created light; / Thou its light, its joy, its crown, / Thou its sun which goes not down."

The melody for "goes not down" sustains the same pitch:

Isolated from the harmony, that's:

The hymn describes Christ as a sun that doesn't descend, and the melody to which that description is sung doesn't descend either.