Pope John XXIII
Mater et Magistra §260
Mater et Magistra: On Christianity and Social Progress
260 This era in which we live is in the grip of deadly errors; it is torn by deep disorders. But it is also an era which offers to those who work with the Church immense possibilities in the field of the apostolate. And therein lies our hope.
Source: Mater et Magistra (Vatican.va)