C.s. Lewis said this quote

[re: the social ethics of Christianity]...the doctrine that imagined heaven on earth is necessary for rigorous attempts to remove present evil, would at once reveal its absurdity. Hungry men seek food and sick men healing nonetheless because they know that after the meal or the cure the ordinary ups and downs of life still await them. I am not, of course, discussing whether very drastic changes in our social system are, or are not, desirable; I am only reminding the reader that a particular medicine is not to be mistaken for the elixir of life.