Old Age
Byron uses imagery to describe the pains of old age, stating that he is in the "yellow leaf" of his life. This imagery of decay is something we see throughout the poem, as the speaker tells us that in his old age he only has "the worm, the canker and the grief." The speaker believes that the joys and excitement of life and love are now behind him, and he should instead devote himself to a nobler cause.
Honour
The speaker realizes that at his time in life he must renounce the pleasures and joys of youth in favor of self-sacrifice and honor. He has a desire to atone for his previously selfish life with an honorable death on the battlefield. Instead of devoting himself to the pursuit of love, the speaker instead decides he will devote himself to honor and nobility.
Legacy
Part of the reason the speaker wants to die on the battlefield is that he wants to leave behind a lasting legacy. Rather than being known for his pleasure-seeking ways and infatuations, the speaker wants to be known for his bravery and honor. As such, we might see his self-sacrificing intentions as being fueled by hubris and self-importance.
