127 Yet, if we look into the matter more carefully and more thoroughly, we shall clearly perceive that, preceding this ardently desired social restoration, there must be a renewal of the Christian spirit, from which so many immersed in economic life have, far and wide, unhappily fallen away, lest all our efforts be wasted and our house be builded not on a rock but on shifting sand.
Source: Quadragesimo Anno (Vatican.va)