Which sentence in Bai Juyi's The Charcoal Man expresses the life dilemma of the Charcoal Man in two bright colors of white and black?

At night, it snowed a foot outside the city, and Xiao drove a charcoal car over the ice. It's dark at night, especially in winter, and the snow is white. Even at night, in the moonlight, it will reflect the glittering and translucent luster. Although the dawn is hidden, you can also imagine the bright scene at dawn, so the combination of main color and hidden color directly renders the arduousness of the road. Charcoal sellers carry the hopes and expectations of a young and old family. Even if the road ahead is difficult, it makes people full of hope and forge ahead.