In Yanmen Enemy at the Gates, the soldiers guarding the city are extremely nervous. Why does the author use the word "Jin Lin" to describe soldiers' bodies?

Suddenly, the situation changed, and a ray of sunshine was transmitted from the clouds and reflected on the armor of the soldiers guarding the city, only to see glittering and dazzling.

At the moment, they are preparing to fight. Here, daylight is used to show the camp and morale of the defenders, and the scene is very wonderful. It is said that Wang Anshi once criticized this sentence, saying, "When dark clouds overwhelm the city, is there still light in the sun?" Yang Shen claimed that he had indeed seen such a scene, accusing Wang Anshi of saying, "Song Lao's headscarf doesn't know poetry." In fact, the truth of art and the truth of life cannot be equated. When the enemy besieged the city, there may not be dark clouds. When the defenders are in array, it is not necessarily the sun that shines and cheers. Dark clouds and sunshine in poetry are the means for poets to create environment and intentions.

Excerpt from Baidu Encyclopedia

Personally, I think Jin Lin, after describing the powerful enemy, reflects the grandeur and majesty of our soldiers from the side, shows the determination and courage of our soldiers, and expresses that they are still determined to fight for the motherland despite their nervousness, which is a fearless performance of the city.