39 Following in the footsteps of Him who "went about doing good and healing" and obeying the command of His who said, "heal the sick" and "make disciples of all nations," the missionary not only speaks learnedly and wisely of the kingdom of God, but also attempts to heal bodies infected with disease and misery. Thus at the same time that he raises the minds, he lifts up the souls, bound to the impiety of superstition and plunged in rough barbarism, to a more civilized life, and commands them to begin to shine with the light of evangelical doctrine.
Source: Saeculo Exeunte Octavo (Vatican.va)