What effect does repetition of lines "Brennan on the moor, Brennan on the moor / bold and undaunted stood young Brennan on the moor" has on the meaning of the poem Brennan on the moor?

The effect of the repetition of lines of the poem Brennan on the moor "Brennan on the moor, Brennan on the moor / bold and undaunted stood young Brennan on the moor" has the meaning that Brennan is most undefeatable opponent and that the narrator wanted the reader to remember Brennan as a mighty warrior.