6 As for our part, having good reason to hope for the consent and support of the public authorities, we have more especially taken care to extend the field of Apostolic labor in these broad regions, appointing further missionary stations, where the Indians can find safety and succor. For the Catholic Church has ever been a fertile mother of Apostolic men, who, pressed by the charity of Christ, are brought to give their lives for their brethren. And today, when so many abhor the faith or fall away from it, the zeal for spreading the Gospel among the barbarous nations is still strong in the clergy and in religious men and holy virgins; and this zeal grows greater and is spread abroad more widely by the power of the Holy Ghost, who helps the Church, His spouse, according to the needs of the time. Wherefore, we think it well to make greater use of those aids which by God's goodness are ready to our hand, in order to deliver the Indians, where their need is greatest. from the slavery of Satan and of wicked men. For the rest, since the preachers of the Gospel had watered these regions, not only with their sweat, but sometimes with their blood, we trust that at length a fair harvest of Christian kindness shall spring forth from their great labors and bear abundant fruit. And now, in order that what you shall do for the benefit of the Indians, whether of your own accord or at our exhortation, may be the more efficacious by the help of our Apostolic authority, we, mindful of the example of our aforesaid predecessor, condemn and declare guilty of grave crime whosoever, as he says, "shall dare or presume to reduce the said Indians to slavery, to sell them, to buy them, to exchange or give them, to separate them from their wives and children, to deprive them of goods and chattels, to transport or send them to other places, or in any way whatsoever to rob them of freedom and hold them in slavery; or to give counsel, help, favor, and work on any pretext of color to them that do these things, or to preach or teach that it is lawful, or to co-operate therewith in any way whatever." Accordingly, we will that the power of absolving penitents in the sacramental tribunal from these crimes shall be reserved to ordinaries of the localities.
Source: Lacrimabili Statu (Vatican.va)