The Bible does not approve of slavery. It permits it. God allowed slavery to exist in both the Old and New Testament times. But this does not mean that slavery was system that God wanted. Slavery was an invention of fallen man - not of God. Nevertheless, God allowed it to exist the way He allows other things to exist that He does not approve of such as murder, lying, rape, theft, etc.
God also worked within the social and economic systems of fallen man and made allowances for the freedom and failures of humanity within those systems. We see this, for example, in Jesus saying that God allowed divorce because of the hardness of peoples' hearts (Matt. 19:8). Divorce is not something that God designed when he created Adam and Eve. But we live in a fallen world, and the truth is, people are sinners and do things contrary to the will of God. But, even though people have murdered, lied, raped, and stolen, God has still used people who've committed these sins to accomplish His divine will. Moses murdered an Egyptian but was used by God to deliver Israel. David committed adultery but was promised to have the Messiah descend from his seed. God desires that people not sin. But, He permits them their freedom and works withing the human-devised systems, like slavery, to accomplish His greater divine will.
This is why slavery was a sad reality that exists in a fallen world where wars led to people being enslaved, famine and debts drove people to indentured servitude, and families sold their children to meet financial obligations. The fact is, slavery was a result of desperate conditions and times. So, biblical admonitions concerning slavery were not aimed at approving it, but working within the social construct of Israel, which was very different from the slavery of the surrounding nations at that time.
- 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 Bible records how God permitted slavery to exist. It was not what he originally designed to be in the world. Furthermore, the slavery of the Bible is not like the slavery that occurred in relatively modern times, where slaves had no rights and were mere property that was sold, traded, and abused. That is not the slavery found in the Bible. After all, Scripture says the slave was a member of the Masters household (Lev. 22:11), was required to rest on the Sabbath (Exodus 20:10; Deut. 5:14), and participate in religious observances (Gen. 17:13; Exodus 12:44; Lev. 22:11). Biblically, property was to be returned to the owner. But the extradition of slaves was prohibited, and they were granted asylum (Deut. 23: 16-17), revealing that they were not property in the chattel sense. The servitude of the Hebrew debts labeled limited to six years (Ex. 21:2; Deut. 15:12). This is vastly different than the chattel slavery of the United States and Europe not so long ago.