[size=3]Always and everywhere, homosexuality has been condemned in Scripture. That will not change. The Church has been faithful in its mission to uphold this moral teaching, in season and out of season. It is a tradition that goes back, not only to apostolic times but to the first book of the Bible in the Old Testament. I will not get into specific Bible verses, since that has been covered well in our tract on homosexuality.
Regarding slavery, the Catholic Encyclopedia explains, “Primitive Christianity did not attack slavery directly; but it acted as though slavery did not exist. …To reproach the Church of the first ages with not having condemned slavery in principle, and with having tolerated it in fact, is to blame it for not having let loose a frightful revolution, in which, perhaps, all civilization would have perished with Roman society.”
Christianity built a society of believers that left no room for slavery. It taught that all are equal: There is neither Jew nor Greek, there is neither slave nor free, there is neither male nor female; for you are all one in Christ Jesus (Galatians 3:28)…For by one Spirit we were all baptized into one body – Jews or Greeks, slaves or free – and all were made to drink of one Spirit (1Cor 12:13).
St. Paul was emphasizing the equality and dignity of all persons in the eyes of God, regardless of their status, national origin or gender.
Early Church Fathers advocated the restoration of rights to the slave that Roman law had denied them.
"In Roman, law, neither legitimate marriage, nor regular paternity, nor even impediment to the most unnatural unions had existed for the slave (Digest, XXXVIII, viii, i, (sect) 2; X, 10, (sect) 5). . .St. John Chrysostom declares that slaves have the marital power over their wives and the paternal over their children (“In Ep. ad Ephes.”, Hom. xxii, 2). He says that ‘he who has immoral relations with the wife of a slave is as culpable as he who has the like relations with the wife of the prince: both are adulterers, for it is not the condition of the parties that makes the crime’ (“In I Thess.”, Hom. v, 2; “In II Thess.”, Hom. iii, 2)” (Catholic Encyclopedia).
(See the continuation of this response below.)