From Viktor Frankl's 1946 "Man's Search for Meaning"

"But one thing I beg of you"; he continued, "shave
daily, if at all possible, even if you have to use a piece
of glass to do it . . . even if you have to give your last
piece of bread for it. You will look younger and the
scraping will make your cheeks look ruddier. If you
want to stay alive, there is only one way: look fit for
work. If you even limp, because, let us say, you have a
small blister on your heel, and an SS man spots this, he
will wave you aside and the next day you are sure to be
gassed. Do you know what we mean by a 'Moslem'? A
man who looks miserable, down and out, sick and
emaciated, and who cannot manage hard physical
labor any longer . . . that is a 'Moslem.' Sooner or
later, usually sooner, every 'Moslem' goes to the gas
chambers. Therefore, remember: shave, stand and
walk smartly; then you need not be afraid of gas. All of
you standing here, even if you have only been here
twenty-four hours, you need not fear gas, except
perhaps you." And then he pointed to me and said, "I
hope you don't mind my telling you frankly." To the
others he repeated, "Of all of you he is the only one
who must fear the next selection. So, don't worry!"