The Pastoral Constitution on the Church in the Modern World turns from principles to specifics with Section 3 of the chapter on culture: “Some More Urgent Duties of Christians in Regard to Culture.”
“It is now possible to free most of humanity from the misery of ignorance.”
This is the theme of article 60. Since our world is at a point where it is actually possible for all to be so educated, we ought to work towards that end.
Here is the footnote:
11. John XXIII, encyclical letter Pacem in Terris: AAS 55 (1963), p. 260.