God did allow for slavery in ancient Israel with some specific laws that were to be followed:

• No one could be a kidnapped victim. All persons had to be voluntarily enslaved (Exodus 21:16). Also, see 1 Timothy 1:10 for the reinforcement that enslavers are guilty of sin no matter if the kidnapped slave is an Israelite or non-Israelite. Paul is writing to Timothy at the church of Ephesus (a Gentile church) and Paul’s list of ungodly acts includes things that apply to all people. This should soundly refute the claim that God approved of the *United States slave trade or blanketly approves of all slavery, because slavery is in the Bible.
• An Israelite would not be treated as a slave if selling themselves into slavery due to poverty (Leviticus 25:39-41).
• No one could beat a slave to death nor permanently injure them (Exodus 21:12; 20-21; 26-27).
• Escaped slaves weren’t forced to go back to their masters (Deuteronomy 23:15-16).
• The bondage of slavery was for a specific amount of time. Further slavery beyond this specific amount of time was voluntary, but it was made permanent (Exodus 21:2-6; Deuteronomy 15:16-17).
• Length of enslavement was different for foreign slaves that the Israelites may have acquired (Leviticus 25:44-46).
• When enslaved Hebrew people were set free they were to be given supplies to take with them (Deuteronomy 15:12-15).

The New Testament has some more things to say about slavery:

• Masters are to treat slaves with justice and fairness (Ephesians 6:9; Colossians 4:1); they should be understanding, as Paul wrote to Philemon, the master of a escaped slave named Onesimus (Philemon).
• Slaves are to be obedient and hardworking (Ephesians 6:5-8; Colossians 3:22; Titus 2:9-10)

Why are slaves encouraged to be obedient and accommodating in what we would today consider a crime against humanity? Because of 1 Corinthians 7:17-24, Colossians 3:23-25; 1 Timothy 6:1.

It is important to understand that by the time the New Testament books were written, slavery surrounding the people of Israel was no longer the Israeli-regulated institution of slavery but the Roman institution of slavery.

*Read about the history of slavery in the United States here,  here and here.