The Bible acknowledged that slavery existed, but Islam went beyond that, by legitimizing slavery.
The Role of Islam in African Slavery
Black Africans were transported to the Islamic empire across the Sahara to Morocco and Tunisia from West Africa, from Chad to Libya, along the Nile from East Africa, and up the coast of East Africa to the Persian Gulf. This trade had been well entrenched for over 600 years before Europeans arrived, and had driven the rapid expansion of Islam across North Africa.By the way, Lebanon still has slaves Here's an article from 1998.
Virtual imprisonment and abuse, the hallmarks of slavery in an earlier time, are now the daily experience of thousands of Sri Lankan women (and others from Africa), employed as servants in today’s Beirut. The authorities are turning a blind eye and the public at large is oblivious to this trade in human labour, which goes on behind the closed doors of the employment agencies and the employer families....
Widespread tacit acceptance of a form of slavery in all but name is evident from the resounding silence which greets anyone who takes the risk of denouncing it. Many people prefer to close their eyes and think of Lebanon in terms of its past sufferings and its present efforts at reconstruction. But what will the country become if it is built on an exploitation of human beings so generalised that it becomes not the exception, but the rule?
[UN] Expert on Trafficking in Persons Ends Visit to Lebanon [September 15, 2005]
In the course of my mission, I have found that a significant number of human beings, women in the majority, are trafficked into and within Lebanon. [snip] Many of my interlocutors, including senior government officials, also acknowledged that widely held attitudes of discrimination on the basis of race, colour, ethnicity, and gender contribute to the prevalence of human trafficking.