Why is slavery permitted in the Bible?

Slavery was permitted in the Bible because of sin in the world. It existed before the Jews were formed as a nation and it existed after Israel was conquered. God allows many things to happen in the world such as storms, famine, murder, etc. Slavery, like divorce, is not preferred by God. Instead, it is allowed. While many nations treated their slaves very badly, the Bible gave many rights and privileges to slaves. So, even though it isn't the best way to deal with people, because God has allowed man freedom, slavery then exists. God instructed the Israelites to treat them properly.

The Bible acknowledged the slave's status as the property of the master (Ex. 21:21; Lev. 25:46).
The Bible restricted the master's power over the slave. (Ex. 21:20)
The slave was a member of the master's household (Lev. 22:11).
The slave was required to rest on the Sabbath (Exodus 20:10; Deut. 5:14).
The slave was required to participate in religious observances (Gen. 17:13; Exodus 12:44; Lev. 22:11).
The Bible prohibited extradition of slaves and granted them asylum (Deut. 23:16-17).
The servitude of a Hebrew debt-slave was limited to six years (Ex. 21:2; Deut. 15:12).
When a slave was freed, he was to receive gifts that enabled him to survive economically (Deut. 15:14).

The reality of slavery cannot be denied. "Slave labor played a minor economic role in the ancient Near East, for privately-owned slaves functioned more as domestic servants than as an agricultural or industrial labor force."1