In the following parable, Jesus clearly approves of beating slaves even if they didn't know they were doing anything wrong.
The servant will be severely punished, for though he knew his duty, he refused to do it. "But people who are not aware that they are doing wrong will be punished only lightly. Much is required from those to whom much is given, and much more is required from those to whom much more is given." (Luke 12:47-48 NLT)
Slaves, obey your earthly masters with deep respect and fear. Serve them sincerely as you would serve Christ. (Ephesians 6:5 NLT)
Christians who are slaves should give their masters full respect so that the name of God and his teaching will not be shamed. If your master is a Christian, that is no excuse for being disrespectful. You should work all the harder because you are helping another believer by your efforts. Teach these truths, Timothy, and encourage everyone to obey them. (1 Timothy 6:1-2 NLT)
The damage of slavery still plagues the Black community whether anyone want to admit it. Blacks have Jesus to thank for their suffering.
For the lying Christian apologists!