What article does Du Fu mean by "the first seven laws in the world"? Why do you say he is a master of poetry?

I hope it helps you: "The Seven Laws in the World are the First" means climbing high. Why is he an all-encompassing poet? Because in the history of China's poetry, Du Fu pushed the realism of China's ancient poetry to a higher stage, which was unprecedented broad, profound and rigorous; In terms of poetic genre, he "draws on the strengths of ancient and modern times and is unique". His five ancient prose, seven ancient prose, five rhythms, seven rhythms, five elements and seven rhythms all reached the first-class level in the Tang Dynasty, and he also created a poetic style with great characteristics and personality of the times-"depression and frustration"