How the brecht showed the theme 'Virture in wartime ' in thestory?

The Model Book also remarks that war "makes the human virtues fatal even to their possessors." This "lesson" appears from the outset of the play, prefiguring the fate of Mother Courage and her children. Telling each of her children's fortunes, Courage will conjure their deaths at the hand of their respective virtues: bravery, honesty, and kindness. Later, The Cook will rehearse this lesson in "The Song of the Great Souls of the Earth." As we will see, Brecht often attributes these virtues ironically. Courage, for example, is often a coward, and Eilif is more a murderer than a brave hero.