Pope Pius XI
Quadragesimo Anno §5
Quadragesimo Anno: On Reconstruction of the Social Order
5 The same feeling those many Catholics, both priests and laymen, shared, whom a truly wonderful charity had long spurred on to relieve the unmerited poverty of the non-owning workers, and who could in no way convince themselves that so enormous and unjust an in equality in the distribution of this world's goods truly conforms to the designs of the all-wise Creator.
Source: Quadragesimo Anno (Vatican.va)