19 So much toil and effort is expended today in mastering and advancing human knowledge that our age glories—and rightly—in the amazing progress it has made in the field of scientific research. But why do we not devote as much energy, ingenuity, and enthusiasm to the sure and safe attainment of that learning which concerns not this earthly, mortal life but the life which lies ahead of us in heaven? Our spirit will rest in peace and joy only when we have reached that truth which is taught in the gospels and which should be reduced to action in our lives. This is a joy which surpasses by far any pleasure which can come from the study of things human or from those marvellous inventions which we use today and are constantly praising to the skies.
Source: Ad Petri Cathedram (Vatican.va)