Quote from peilthetraveler:
No its not. Only certain forms of slavery like kidnapping someone and making them your slave is something God frowns upon. Or adding more and more debt to a slave so that he can never buy himself out. If I remember right, the law used to be that after 7 years a man was to be set free from his servitude.
You will also find it interesting that slaves back in biblical times loved their masters so much that when they were freed, many chose to stay with their masters as it meant a better way of life for them.