20 In the meantime, while by a more strenuous application of ingenuity and labor new roads are being made, and new commercial enterprises undertaken in the lands of Africa, let apostolic men endeavor to find out how they can best secure the safety and liberty of slaves. They will obtain success in this matter in no other way than if, strengthened by divine grace, they give themselves up to spreading our most holy faith and daily caring for it, whose distinguishing fruit is that it wonderfully flavors and develops the liberty "with which Christ made us free."(26) We therefore advise them to look, as if into a mirror of apostolic virtue, at the life and works of St. Peter Claver, to whom We have lately added a crown of glory.(27) Let them look at him who for fully forty years gave himself up to minister with the greatest constancy in his labors, to a most miserable assembly of Moorish slaves; truly he ought to be called the apostle of those whose constant servant he professed himself and gave himself up to be. If they endeavor to take to themselves and reflect the charity and patience of such a man, they will shine indeed as worthy ministers of salvation, authors of consolation, messengers of peace, who, by God's help, may turn solicitude, desolation, and fierceness into the most joyful fertility of religion and civilization.
Source: In Plurimis (Vatican.va)