“It is monstrous for one to live in luxury while many are in want.”

Cited by a character in J. D. Salinger's The Catcher in the Rye (1951) as a statement of Stekel, this has often been attributed to Salinger, and may actually be a paraphrase by him of a statement of the German writer Otto Ludwig (1813-1865) which Stekel himself quotes in his writings:
Das Höchste, wozu er sich erheben konnte, war, für etwas rühmlich zu sterben; jetzt erhebt er sich zu dem Größern, für etwas ruhmlos zu leben.
The highest he could raise himself to was to die gloriously for something; now he rises to something greater: to live humbly for something.
Gedanken Otto Ludwigs : Aus seinem Nachlaß ausgewählt und herausgegeben von Cordelia Ludwig (1903) p. 10 http://archive.org/stream/gedankenottolud00ludwgoog#page/n39/mode/2up; this is quoted by Stekel in "Die Ausgänge der psychoanalytischen Kuren" in Zentralblatt für Psychoanalyse : Medizinische Monatsschrift für Seelenkunde (1913), p. 188 http://archive.org/stream/ZB_III_1913_4_5_k#page/n19/mode/2up, and in Das liebe Ich : Grundriss einer neuen Diätetik der Seele (1913), page 38 http://books.google.de/books?id=PgFAAAAAIAAJ&q=r%C3%BChmlich.
Misattributed

Quoted by Salinger as a statement of the psychoanalyst Wilhelm Stekel in The Catcher in the Rye, this has often been attributed to Salinger, and it may actually be a paraphrase by him of a statement of the German writer Otto Ludwig (1813-1865) which Stekel himself quotes in his writings:
Das Höchste, wozu er sich erheben konnte, war, für etwas rühmlich zu sterben; jetzt erhebt er sich zu dem Größern, für etwas ruhmlos zu leben.
The highest he could raise himself to was to die gloriously for something; now he rises to something greater: to live humbly for something.
Gedanken Otto Ludwigs : Aus seinem Nachlaß ausgewählt und herausgegeben von Cordelia Ludwig (1903), p. 10 http://archive.org/stream/gedankenottolud00ludwgoog#page/n39/mode/2up; this is quoted by Stekel in "Die Ausgänge der psychoanalytischen Kuren" in Zentralblatt für Psychoanalyse : Medizinische Monatsschrift für Seelenkunde (1913), p. 188 http://archive.org/stream/ZB_III_1913_4_5_k#page/n19/mode/2up, and in Das liebe Ich : Grundriss einer neuen Diätetik der Seele (1913), page 38 http://books.google.de/books?id=PgFAAAAAIAAJ&q=r%C3%BChmlich.
Disputed

As quoted in Translation as Transhumance by Mireille Gansel (Feminist Press, 2017)

Source: Why We Fail as Christians (1919), p. 37
Context: Hard manual labor revealed many things to Tolstoy. As soon as he began to do regular physical work the greater part of his luxurious habits and wants, which were so numerous when he had been physically idle, disappeared.

"Robert Denning Dies at 78; Champion of Lavish Décor", by Mitchell Owens, Sep. 4, 2005, New York Times obituary

Williams-Akoto. "My Home: Stella Vine, artist" http://www.independent.co.uk/life-style/house-and-home/property/my-home-stella-vine-artist-517456.html, The Independent, (2005-11-30)
On reading.

BBC Radio broadcast, Russian service, as quoted in The Listener (15 February 1979).

The Beauty of Life (1880).