Here are the first two phrases, which are also repeated as the second two phrases:
The first two lines of the hymn are "Rise, ye children of salvation, / All who cleave to Christ, the Head." "Head" is sung to a C, and since the tune is in C major, there's also a musical sense of this centrality.
The second two lines in the first verse are "Wake, arise, O mighty nation, / Ere the Foe on Zion tread." Both "Rise, ye children of salvation" and "Wake, arise, O might nation" are sung to generally ascending phrases (from C to G), and this provides a sense of "rise" and "arise."