What lessons of war are learned in chapter 21?

No firing threatens the regiment as they return to their blue lines. The men are nervous as they go, suspecting that they may be fired on at anytime. When they get back to their lines, they are peppered with sarcastic questions, asking where they have been and why they are coming back. The men of the regiment make no reply, except one soldier who challenges any one of them to a fistfight. Henry is stung by these remarks. He glowers at the men who ridicule him.Henry learns that the optics (how things look) in war is more important than what a soldier does or does not do, even among his own men.