Yang Jiong wrote "Fighting against the North". What is the theme of this poem? urgent

The Battle of the South of the City is a five-character poem written in the old Yuefu style. Although the poem tells about the military career of expeditionary frontier fortress in the tone of a combatant, it is different from the Battle of the South of the City written by Han Yuefu. The hero in the poem is full of pride, confidence and hope for victory when describing the war. The style of this poem is vigorous and powerful, full of strong patriotism.