17 You well know where it is necessary that you exercise a more discerning vigilance and what program of action should be marked out for priests and faithful in order that the religion of Christ may overcome the obstacles in its path and be a luminous guide to the minds of men, govern their morals and, for the sole purpose of salvation, permeate the marrow and the arteries of human society. The progress of exterior and material possessions, even though it is to be considered of no little account, because of the manifold and appreciable utility which it gives to life, is nonetheless not enough for man who is born for higher and brighter destinies. Created indeed to the image and likeness of God, he seeks God with a yearning that will not be repressed and always groans and weeps if he places the object of his love where Supreme Truth and the Infinite Good cannot be found.
Source: Sertum Laetitiae (Vatican.va)