Pope John XXIII
Mater et Magistra §107
Mater et Magistra: On Christianity and Social Progress
107 And this is as it should be. Work, which is the immediate expression of a human personality, must always be rated higher than the possession of external goods which of their very nature are merely instrumental. This view of work is certainly an indication of an advance that has been made in our civilization.
Source: Mater et Magistra (Vatican.va)