To our minds slavery is abhorrent because our understanding of it is shaped by the slave trade, where individuals are involuntarily removed from their homes, chained, and forced to work for tyrannical masters without any independence.
This is plainly condemned in scripture in Exodus 21:16 where we read, “And he that stealeth a man, and selleth him, or if he be found in his hand, he shall surely be put to death.”
We need to keep in mind the context of the day. This is a time without any government welfare, so what could someone do if they could not provide a living for themselves? They could become subject to a master, who in return for their services, would provide for them and their family.
For the Christian, the biblical teaching on slavery is particularly relevant, because if you are truly a Christian, then Jesus Christ is your Lord and Master, and you are called to literally be His slave. Is that reflected in your life?