What is the theme of Yang Jiong's "Occupy the South"?

Original: Fight in the south of the city, die in the north, die in the wild and eat without burial. Call me Wu; Come; Guest! I dare not bury the dead in the wild, but can I escape carrion? The water depth is stimulating, and Puwei is invisible; The owl rode to death, and Xu hesitated. Why does the room in Lianglou face south? Why the north? What can you eat if you don't get rice? Willing to be a loyal minister? Think about your son and be a good minister. A good minister thinks about it sincerely: attack in the morning and don't return at night! Objective: Reflected in the continuous war history, the soldiers who fought in the battlefield lived a cruel life and the scene was bleak. However, the hearts of the soldiers are full of bright sunshine, and they are eager for peace.