Pope John XXIII
Mater et Magistra §130
Mater et Magistra: On Christianity and Social Progress
130 One advantage which would result from the adoption of this plan would be that it would be easier to keep track of the movement of the working force set free by the progressive modernization of agriculture. Facilities could then be provided for the training of such people for their new kind of work, and they would not be left without economic aid and the mental and spiritual assistance they need to ensure their proper integration in their new social milieu.
Source: Mater et Magistra (Vatican.va)