The tune to which the hymn is sung is "Webb" (apparently named after its composer George J. Webb), and the first phrase starts with two ascending intervals (a fourth and then a third):
In each verse, the text sung to these ascending intervals is "Stand up, stand up," so in both the text and the tune, there's a "stand[ing] up."
The third musical phrase is the same as the first, and in the first verse, the text there is "Lift high His royal banner." The "lift high" is sung to that ascending fourth, so there's a musical/textual connection there too.
