The Bible applies perfectly to all its readers in ancient times, in modern times, and all times in between. In order for that to be true, though, some passages need to be read within their unique cultural context. For example, Paul writes:
Slaves, obey your earthly masters with respect and fear, and with sincerity of heart, just as you would obey Christ.
Obey them not only to win their favor when their eye is on you, but as slaves of Christ, doing the will of God from your heart.
Serve wholeheartedly, as if you were serving the Lord, not people.
In this passage, he references the current laws and standards. Slavery wasn’t a controversial issue of social justice in ancient times. It was the normal way of life. If you weren’t a slave, you were probably part of a household that owned slaves. A slave wasn’t just property; wives and children were also property. A slave was a slave for life, alienated, treated with violence, and generally dishonored.
In this culture where slavery was normal, Paul instructs slaves how to act. Few of us believe Paul was writing a rule for all future cultures. That distinction will be important later as we analyze biblical texts on sex.
Jesus also makes reference to servants (i.e., slaves) in his parables. Neither Jesus, nor Paul, nor any Biblical writer ever mentions opposition to the institution of slavery. As we saw in the above, New Testament writers told slaves how to be better slaves, not how to escape or change the slavery system.
The Old Testament supports slavery even more. Moses, the lawgiver, describes how slaves can be purchased and handed down as property.
Your male and female slaves are to come from the nations around you; from them you may buy slaves.
You may also buy some of the temporary residents living among you and members of their clans born in your country, and they will become your property.
You can bequeath them to your children as inherited property and can make them slaves for life, but you must not rule over your fellow Israelites ruthlessly.
Most folks today who read the hundreds of pro-slavery verses in the Bible conclude that these writings were meant to be taken in cultural context. Certainly God does not command slavery or even endorse it. He allowed comments to be made about a current practice.
But, if you lived in the American South in the mid-1800s, owned slaves, and loved Jesus, you likely would have interpreted these Bible verses differently. How could these Northern agitators—the so-called abolitionists—conclude that God was on their side?
In fact, even Christian slaves struggled with how to interpret biblical teachings on slavery. Frederick Douglass, who was born a slave and escaped north in his mid-20s, wrote, “I had at times asked myself the question, ‘May not my condition after all be God’s work, ordered for a wise purpose, and if so, is not submission my duty?’” 
Douglass struggled with the concept of being a “slave for life.” In his younger years, he accepted the brutality he encountered, but the thought that he would never be anything but someone else’s property—never have a permanent wife, never be certain when his children would be sold away from him—made that life unbearable.
Douglass decided to escape. He expected to be tortured and to die. He consciously chose death over a continued life of slavery. He knew slavery was a great evil, both to the slaves and to the slave holders, but he’d heard the pro-slave verses preached as truth his entire life.
Now let’s try to imagine what our life might be like in America in the 1850s as a slave. The master could rape you (though it’s not rape because you’re his property). The master could make you work anywhere and take all your wages. The master could sell your children. The master was not allowed by law to teach you to read. The master could kill you.
On the other hand, say you lived in the North. You probably didn’t think about slavery often. It was an issue far away that affected other people. You’re busy enough with your own life and don’t need to solve other people’s problems. No one made you the General Manager of the Universe.
But if you lived in the South and weren’t a slave, you grew up with slavery being a normal part of the culture. Your minister preached regularly on pro-slavery verses. You believed the kindest thing you could do for the colored folks was to keep them in slavery since they weren’t capable of taking care of themselves.
How would you have interpreted the Bible if you were in one of these situations above in the 1850s? How would you have lived? Would you have said about slavery, “The Bible says it, I believe it and that settles it”? Or would you have been an abolitionist?
Most abolitionists were ardent Christians who felt the Holy Spirit leading them to declare slavery evil and fight against it. Douglass writes about the Quakers who helped him gain freedom at great risk to themselves. He marvels at those who “took me in when I was a stranger” and “fed me when I was hungry.” Douglass (and all slaves eventually) felt the love of Jesus through those works.
Jesus gave us a simple test. Every good tree bears good fruit, but a bad tree bears bad fruit. William Wilberforce showed the bad fruits of slavery to the British Empire in the early 1800s. The American Abolitionists highlighted those bad fruits in the mid-1800s, culminating in the Civil War. As the laws changed, churches evaluated the scriptural teaching vs the bad fruits concept.
Slavery was a case in which biblical interpretation and church doctrine changed dramatically. What are some others?
 I Pet 2:17-20 (NIV 2011)
 Orlando Patterson, Slavery and Social Death (Cambridge MA: Harvard College, 1982), 13.
 You could argue that Paul told the owner of Onesimus to give him his freedom to help Paul, but that wasn’t an argument against the institution of slavery itself.
 Abraham, the great man of faith in the Bible, was also a slave owner (Gen 12:5). Solomon writes that slaves will need to be beaten for correction (Prov 29:19).
 Leviticus 25:44-46
 Supposedly 326 pro-slavery Bible verses, though I haven’t counted.
 Douglass, Frederick, The Life and Times of Frederick Douglass, (Mineola, NY: Dover Publications, Inc, 2003), 141.
 Ibid. 143-4.
 Matthew 7:15-20