3 Besides protecting freedom, another more serious apostolic concern orders Usto spread the teaching of the Gospel in Africa. This teaching should bathe thoseinhabitants living in darkness and blind superstition with the light of divinetruth, by which they can become co-heirs with Us of the kingdom of God. We arethe more concerned about this because those who have received this light havealso shaken off the yoke of human slavery. Wherever Christian customs and lawsare in force, wherever religion establishes that men serve justice and honorhuman dignity, wherever the spirit of brotherly love taught by Christ spreadsitself, there neither slavery nor savage barbarism can exist. Rather, mildnessof character and civilized Christian liberty flourish there. Many apostolic men, like standard-bearing soldiers of Christ, go to the African interior to shed their sweat, even life itself for the welfare of their brothers. But "the harvest indeed is great; the laborers are few." Therefore, many others are needed where that scandalous commerce is conducted. They must be full of the spirit of God, fearing neither danger, nor inconveniences, nor labors to spread the teaching of Christ, which is joined to true freedom. This might enlighten even that wretched part of the human race with the revelation of His divinity and release it from the mire of superstition and misery in which it has lain abandoned and neglected for so long.
Source: Catholicae Ecclesiae (Vatican.va)