It is obviously symbolic that "dark clouds" overwhelm the city and even overwhelm it. The word "black" on the "cloud" is naturally not used to symbolize our army but the enemy. The enemy's siege is so fierce, then our army will only have a chance to live in deus ex. "A bright light spreads to the sun", which is in sharp contrast with the previous sentence in color and form. It clearly contains joy and praise, and of course refers to our army. At first, the city was besieged by dark clouds, and then the dark clouds collapsed and the red sun was in the sky. The shining armor of our soldiers was like patches of gold scales in the sun, dazzling people's eyes. That is to say, we have fought our way out of the isolated city and defeated the enemy soldiers.
I guess these two sentences reflect
1. Things are developing from qualitative change to quantitative change.
2, the methodology of seeking truth from facts
3, the principle of causality, because of the invasion of the army, so our army defended.