It's sung to the tune "Winchester New," the first phrase of which has a cross inscription:
I don't think there's any connection between this cross inscription and the hymn's text; however, in the sixth verse, the line here is "Now rise, faint hearts, be resolute," so the ascent in the melody (a fourth: F to Bb) connects to the call to "rise."
In the fifth verse, there's a descent in the melody that musically represents "Adam's fall." The whole verse is:
The Father's word, the Spirit's flightThe third line is sung to this musical phrase:
Anointed Christ in glorious sight
As God's own choice, from Adam's fall
To save the world and free us all.
There's an-other cross inscription here, but I don't think there's any connection between this one and the hymn text either.
Finally, there's a descent in the last phrase that mirrors the descent mentioned in last line of the third verse: the Holy Spirit "Descended on Him from above":