It means: bear justice and great responsibility with generous shoulders, and write wonderful articles with flexible hands to arouse people's consciousness. This sentence is a couplet written by Li Dazhao to his friends, and it is also a portrayal of his life. Morality is morality and justice, and "shouldering morality with iron shoulders" means carrying forward the burden of morality and justice with strong determination and perseverance and the strength of life. "Writing articles" refers to seeking truth, propagating lofty ideals and progressive political opinions, so as to arouse people's consciousness.