43 Nevertheless We cannot deny that there is still much to be done in the way of spiritual renovation. Even in Catholic countries there are still too many who are Catholics hardly more than in name. There are too many who fulfill more or less faithfully the more essential obligations of the religion they boast of professing, but have no desire of knowing it better, of deepening their inward conviction, and still less of bringing into conformity with the external gloss the inner splendor of a right and unsullied conscience, that recognizes and performs all its duties under the eye of God. We know how much Our Divine Savior detested this empty pharisaic show, He Who wished that all should adore the Father "in spirit and in truth." The Catholic who does not live really and sincerely according to the Faith he professes will not long be master of himself in these days when the winds of strife and persecution blow so fiercely, but will be swept away defenseless in this new deluge which threatens the world. And thus, while he is preparing his own ruin, he is exposing to ridicule the very name of Christian.
Source: Divini Redemptoris (Vatican.va)