The third verse begins with the lines "Help us to serve You evermore / With hearts both pure and lowly," sung to these phrases:
The first syllable of "lowly" is sung to the lowest note (D) in the phrase (the lowest note in the hymn, in fact), giving a sense of its meaning.
These musical phrases are repeated as the third and fourth phrases, and in the first verse, the text here is "In You she [the Church] trusts, before You bows, / And waits for Your salvation." Reflecting this "bow[ing]," the melody descends (diatonically from B to F#).
