85 It must be admitted that men very often find themselves in a sad state because they do not give enough thought and consideration to these things. So We call upon men of deep thought and wisdom—Catholics and Christians, believers in God and devotees of truth and justice, all men of good will—to take as their own Christ's injunction, "Seek and you shall find." (69) Blaze the trails to mutual cooperation among men, to deeper knowledge and more widespread charity, to a way of life marked by true brotherhood, to a human society based on mutual harmony.
Source: Populorum Progressio (Vatican.va)