 From this it follows that it is not contrary to the natural and divine law for a slave to be sold, bought, exchanged or donated, provided that in this sale, purchase, exchange or gift, the due conditions are strictly observed which the approved authors likewise describe and explain.Among these conditions the most important ones are that the purchaser should carefully examine whether the slave who is put up for sale has been justly or unjustly deprived of his liberty, and that the vendor should do nothing which might endanger the life, virtue or Catholic faith of the slave who is to be transferred to another's possession.