Elie Wiesel, we know, survived the most horrendous chapter in human history, the Holocaust. Six million of Europe's Jewish population were murdered, with millions more Russian prisoners, homosexuals, Roma, and others deemed racially inferior executed, starved or denied medical care and left to die of disease. His experiences in the German concentration camps allowed him to observe the razor-thin line between those selected for immediate execution in the gas chambers and ovens and on the firing lines where thousands were systematically shot in the back of the head, their bodies falling into ditches for mass burial.
In the chapter in Night in which Wiesel describes another such experience, with the margin between life and death perilously thin, one of the most dangerous of Germany's many war criminals, Dr. Joseph Mengele, is personally overseeing the latest selection of prisoners for execution, with those whose names are being recorded destined for immediate death. Wiesel, as with the other prisoners, knows that Mengele and his minions will only spare those who appear healthy enough to continue to perform the brutal manual labor that was the price for survival. This is the context in which the young Elie repeats to himself, "you are too skinny…you are too weak…you are too skinny, you are good for the ovens … The race seemed endless; I felt as though I had been running for years…You are too skinny, you are too weak . . ."
If one reads the full passage, it is self-evident why he tells himself that he is "too skinny" and "too weak." This helps reveal his experience since his repetition is because such a physical state would render him useless to the Third Reich, with the consequence being his dispatch to the ovens or the gas chambers. That is why, later in his story, Wiesel describes the horror with which an old family friend, Meir Katz, confesses to Elie's father that "Shlomo, I am getting weak. My strength is gone. I won't make it . . ." If the Nazi's determined that an inmate was too weak to continue as a laborer, then they killed that individual without hesitation and, of course, without remorse. Wiesel repeats that phrase to himself because he is frightened that he will be selected for death because he believes that he no longer appears sufficiently physically-fit.