This passage is taken from the latter part of Chapter 9 of Remarque's stirring novel. Paul Baumer has been returned to the front and searches for his comrades, but is forced to jump into a shell hole as he loses his direction and is under fire. When night falls, Paul pulls out his knife and starts to crawl out and find his way; however, a soldier suddenly falls upon him and in his fear Paul stabs him mercilessly. Because he hears machine guns firing, Paul cannot leave the hole and is faced with his victim. It is then that Paul no longer perceives the man as an enemy, but as a suffering person upon whom he has inflicted a fatal sentence. Calling the man "comrade," Paul gives him water and attempts to ease his pain. But, "every gasp lays [his] heart bare" as Paul is ridden with guilt for slaying a fellow human being.
This is the first time I have killed with my hands, whom I can see close at hand, whose death is my doing.
The victim's gasping tears at Paul as the "invisible dagger" of regret for having inflicted mortality upon an innocent man sits heavily upon his heart. Clearly, this poignant scene underscores the theme of the futility of war.