The hymn is sung to the tune "O quanta qualia." Here's the second musical phrase:
In the second verse, the text here is "Lord God of Sabaoth, nearest Your throne," continuing the sense from the previous line: "These are Your ministers, these are Your own" ("Lord God of Sabaoth" is a vocative). "Nearest" is sung with a melisma (A G A), giving a sense of the superlative nature of the adjective (more notes for a higher degree).
The third musical phrase:
In the fourth verse, the text here is "Till, where their anthems they ceaselessly pour." "Pour" is sung with a descending melisma (A G), giving something of a sense of its meaning, although it's used metaphorically.
The fourth musical phrase:
In the first verse, the text here is "Praise the Thrice Holy One, serving but Him." "Holy" is sung to three notes (A G G), matching the modifying adverb "Thrice."
In the third verse, the text is "Then all the sons of God shouted for joy" (from Job 38:7). "Sons" is sung with a melisma (A G), providing a sense of the entirety of "all," and "joy" is sung with a melisma (G F), giving a sense of ebullience.