95 It realizes only too well the enormous difficulties of such a mission. It is well aware of the numerical disproportion between itself and the rest of the human race. It knows its own limitations, its own shortcomings and the failings of its own members. It realizes too that the acceptance of the gospel does not depend on any apostolic endeavors of its own, nor on the existence of the right temporal conditions. Faith is a gift of God. He alone determines in the world the order and the time of salvation. The Church does, however, realize that it is the seed, as it were, the leaven, the salt and the light of the world. Fully conscious of all that is new and remarkable in this modern age, it nevertheless holds its place in a changing world with sincere confidence, and says to men: "Here in my possession is what you are looking for, what you need." Its promise is to one of earthly happiness, but it does nevertheless provide the best means for the attainment of earthly happiness, namely, light and grace; and it teaches men about their future life which transcends nature. In addition it speaks to them of truth, justice, freedom, progress, concord, civilization and peace. The Church well knows the value of these things. It knows them in the light of Christ's revelation. It has a message, therefore, for everyone: boys and girls, young men and women, scientists and scholars, working men and men of every class in society, professional men and politicians; but especially the poor, the unfortunate, the sick and the dying-in a word, everybody.
Source: Ecclesiam Suam (Vatican.va)