Pope John XXIII
Pacem in Terris §20
Pacem in Terris: On Establishing Universal Peace in Truth, Justice, Charity, and Liberty
20 A further consequence of man's personal dignity is his right to engage in economic activities suited to his degree of responsibility.(16) The worker is likewise entitled to a wage that is determined in accordance with the precepts of justice. This needs stressing. The amount a worker receives must be sufficient, in proportion to available funds, to allow him and his family a standard of living consistent with human dignity. Pope Pius XII expressed it in these terms: "Nature imposes work upon man as a duty, and man has the corresponding natural right to demand that the work he does shall provide him with the means of livelihood for himself and his children. Such is nature's categorical imperative for the preservation of man."(17)
Source: Pacem in Terris (Vatican.va)