Adorno commenting on Arnold Schönberg’s A Survivor of Warsaw (1947):

The so-called artistic rendering of the naked physical pain of those who were beaten down with rifle butts contains, however distantly, the possibility that pleasure can be squeezed from it.  The morality that forbids art to forget this for a second slides off into the abyss of its opposite.   The aesthetic stylistic principle, and even the chorus’s solemn prayer, make the unthinkable appear to have had some meaning; it becomes transfigured, something of its horror is removed.  By this alone an injustice is done the victims, yet no art that avoided the victims could stand up to the demands of justice.

Theodor W. Adorno, ‘Commitment’, in Can One Live after Auschwitz: A Philosophical Reader, ed. by Rolf Tiedemann, trans. by Rodney Livingston and others (Stanford: Stanford University Press, 2003), pp. 240-58 (p. 252).