|For it is so written in|
In modern times, slavery is generally considered immoral. Historically speaking, on the other hand—in the Roman Empire and in much of Europe and the "New World" between the fifteenth and nineteenth centuries—opinions have varied more widely, tending toward a view of slavery as morally acceptable (except possibly by the slaves).
Slavery was also an important facet of life in biblical times. Both the Old and the New Testaments have instructions regarding slaves which most Jews and Christians disregard. However, some fringe Christian Biblical literalists, notably those who believe in Dominionism, argue that biblcal instructions regarding slavery and its institutions are still relevant today. 
 Slavery in the Old Testament
The Bible identifies different categories of slaves including female Hebrew slaves, male Hebrew slaves, non-Hebrew and hereditary slaves. These were subject to different regulations.
Female Hebrews could be sold by their fathers and enslaved for life (Exodus 21:7-11), but under some conditions.
Male Hebrews could sell themselves into slavery for a six year period to eliminate their debts, after this period they might go free. Evangelical Christians, especially those who subscribe to Biblical inerrancy, will commonly emphasize this debt bondage and try to minimise the other forms of race-based chattel slavery when attempting to excuse the Bible for endorsing slavery.
Non-Hebrews, on the other hand, could (according to Leviticus 25:44) be subjected to slavery in exactly the way that it is usually understood. The slaves could be bought, sold and inherited when their owner died. This, by any standard, is race- or ethnicity-based, and must necessarily involve some sort of slave trade.
Hereditary slaves were born into slavery and there is no apparent way by which they could obtain their freedom.
So the Bible endorses various types of slavery, see below - though biblical literalists only want to talk about one version and claim that it wasn't really so bad.
 Types of slavery
As previously stated the bible endorsed different types or grades of slavery.
 Female Hebrew slaves
Female Hebrew slaves were to be treated differently from males. Parents could sell their daughters into slavery. (Exodus 21:7-11 NASB)
7If a man sells his daughter as a female slave, she is not to go free as the male slaves do. 8If she is displeasing in the eyes of her master who designated her for himself, then he shall let her be redeemed. He does not have authority to sell her to a foreign people because of his unfairness to her. 9If he designates her for his son, he shall deal with her according to the custom of daughters. 10If he takes to himself another woman, he may not reduce her food, her clothing, or her conjugal rights. 11If he will not do these three things for her, then she shall go out for nothing, without payment of money.
 Male Hebrew slaves
Exodus 21:2-6 (NASB):
2If you buy a Hebrew slave, he shall serve for six years; but on the seventh he shall go out as a free man without payment. 3If he comes alone, he shall go out alone; if he is the husband of a wife, then his wife shall go out with him. 4If his master gives him a wife, and she bears him sons or daughters, the wife and her children shall belong to her master, and he shall go out alone. 5But if the slave plainly says, ‘I love my master, my wife and my children; I will not go out as a free man,’ 6then his master shall bring him to God, then he shall bring him to the door or the doorpost. And his master shall pierce his ear with an awl; and he shall serve him permanently.
It is interesting to note that if a slave wishes to remain with his wife and family he must submit to his master for life.
On the other hand Hebrew slaves - and only those Hebrew slaves who entered slavery "voluntarily" - got some severance package as described in Deuteronomy 15:12-15 (NASB):
12If your kinsman, a Hebrew man or woman, is sold to you, then he shall serve you six years, but in the seventh year you shall set him free. 13When you set him free, you shall not send him away empty-handed. 14You shall furnish him liberally from your flock and from your threshing floor and from your wine vat; you shall give to him as the LORD your God has blessed you. 15You shall remember that you were a slave in the land of Egypt, and the LORD your God redeemed you; therefore I command you this today.
 Non-Hebrew Slaves
If the Israelites wanted full slaves they were instructed in Leviticus 25:44-46 (NASB):
44As for your male and female slaves whom you may have—you may acquire male and female slaves from the pagan nations that are around you. 45Then, too, it is out of the sons of the sojourners who live as aliens among you that you may gain acquisition, and out of their families who are with you, whom they will have produced in your land; they also may become your possession. 46You may even bequeath them to your sons after you, to receive as a possession; you can use them as permanent slaves. But in respect to your countrymen, the sons of Israel, you shall not rule with severity over one another.
 Hereditary Slaves
The children of slaves were born into slavery. Exodus 21:4 (NASB):
If his master gives him a wife, and she bears him sons or daughters, the wife and her children shall belong to her master, and he shall go out alone.
 Beating slaves
Beating slaves was perfectly allowable under the following rules:
Exodus 21:20-21 (NASB): 20If a man strikes his male or female slave with a rod and he dies at his hand, he shall be punished. 21If, however, he survives a day or two, no vengeance shall be taken; for he is his property.
Exodus 21:26-27 (NASB): 26If a man strikes the eye of his male or female slave, and destroys it, he shall let him go free on account of his eye. 27And if he knocks out a tooth of his male or female slave, he shall let him go free on account of his tooth.
 Abduction and slave trade
Hebrews were not allowed to abduct fellow Hebrews and sell them.
Exodus 21:16 (NASB): 16He who kidnaps a man, whether he sells him or he is found in his possession, shall surely be put to death.
Given that the Hebrews were instructed in Leviticus 25 v 44 to obtain their slaves from the people around them, it is evident that this injunction to not abduct people referred to Hebrews and not non-Hebrews. Obtaining and selling non-Hebrews was evidently not a problem.
 Escaped slaves
An escaped slave could not be handed over to his master, and would gain full citizenship among Israelites:
Deuteronomy 23:15-16 (NASB): 15You shall not hand over to his master a slave who has escaped from his master to you. 16He shall live with you in your midst, in the place which he shall choose in one of your towns where it pleases him; you shall not mistreat him.
However, as BibleTrack complementaries put it regarding Deut 23:15
“”Most students of the Old Testament agree that this regulation concerns a slave who has escaped from his master in some foreign land and sought refuge in Israel. We do know that, in addition to slaves captured in battle, debt slavery and voluntary slavery existed in Israel and was protected by law, so it seems unlikely that this law applies to those two categories of slaves. We simply aren't given any detail beyond these two verses.
 Slavery in the New Testament
The New Testament makes no condemnation of slavery and does no more than admonish slaves to be obedient and their masters not to be unfair. Paul, or whoever wrote the epistles, at no time suggested there was anything wrong with slavery. One could speculate that this might have been because he wanted to avoid upsetting the many slave owners in the early Christian congregations or to keep on good political terms with the Roman government. Or, more probably, he simply thought slavery was an acceptable fact of life as did practically everyone else at the time.
Ephesians 6:5-8 (NASB): 5Slaves, be obedient to those who are your masters according to the flesh, with fear and trembling, in the sincerity of your heart, as to Christ; 6not by way of eyeservice, as men-pleasers, but as slaves of Christ, doing the will of God from the heart. 7With good will render service, as to the Lord, and not to men, 8knowing that whatever good thing each one does, this he will receive back from the Lord, whether slave or free.
Christian slaves were told to obey their masters "for the sake of the cause" and be especially obedient to Christian masters:
1 Timothy 6:1-2 (NASB): 1All who are under the yoke as slaves are to regard their own masters as worthy of all honor so that the name of God and our doctrine will not be spoken against. 2Those who have believers as their masters must not be disrespectful to them because they are brethren, but must serve them all the more, because those who partake of the benefit are believers and beloved. Teach and preach these principles.
There are instructions for Christian slave owners to treat their slaves well.
Ephesians 6:9 (NASB): 9And masters, do the same things to them, and give up threatening, knowing that both their Master and yours is in heaven, and there is no partiality with Him.
One passage often cited by apologists as supposed evidence for New Testament condemnation of slavery is 1 Timothy 1:10. However, as the King James version accurately translates, this condemnation is of "men stealers" (Greek: andrapodistais), i.e. slave raiders who kidnapped and sold people as slaves, not slave traders or slave holders in general. So Paul only singled out slave raiders to be considered "lawless and rebellious," and to be categorized with murderers, homosexuals, liars and oath breakers.
The rather bland admonishment to slave masters by Paul is more than balanced by the demands for absolute obedience made of slaves. It is also rather telling that the masters are likened to God and Jesus, while the masters are simply told that they have a higher lord. So much for Jesus as the embodiment of the underdog - Paul could have pointed to Jesus' imprisonment and death as a cautionary tale to slave masters that even humble(d) characters can be important.
Before the apologist plays the "but Jesus didn't condone slavery"-card, following all these Pauline examples, try reading Matthew 18:25, where Jesus uses slaves in a parable and has no qualms about recommending that not only a slave but also his wife and family be sold, while in other parables Jesus recommends that disobedient slaves should be beaten (Luke 12:47) or even cut down (Matthew 24:51).
 Moral relativism
This is probably one of the clearest example of religious moral relativism.
Most modern Christians prefer to avoid, or are unaware of, these sections of the Bible. If forced to explain Biblical justification for slavery, they may come up with something, but fortunately Christians as a group think it would be wrong to reintroduce slavery. Christian attempts to justify what is in the Bible can lead to them sanctioning things that most moral humanists, and even most Christians, would say are wrong, as can be seen from the quote below.
Here is a recent Christian attempt to justify slavery:
"They 'shall be of the heathen' is the key phrase here. God approved of slavery in this instance only because it was His hope that those who became slaves of the Israelites from foreign nations might "be saved." Even though they would lose their earthly freedom, God hoped that they would gain eternal freedom by coming to know Him, which is far more important." 
 Attempts to justify the Bible's slavery passages
Argument 1: "Slavery in the Bible was more enlightened than that of 17th-19th Century America and other Ancient Near East cultures."
- Even granting this point for the sake of argument, this fails to answer the simple question: is owning another human ever moral, or not? The relative kindness of a slave owner does not enter into the basic moral question of owning other humans as property.
Argument 2: "They could be let go after 6 years" or "It was a mechanism for protecting the those who could not pay their debts." (A.k.a. "Debt bondage")
- Only some Hebrew male slaves were to be freed in the 7th year (Exodus 21:26). Slaves from surrounding countries could be kept as property forever (Leviticus 25:44-46). A further exception pertains to women whose fathers sold them into slavery, and for whom there was no release after six years (Exodus 21:7).
Argument 3: The Bible restricted slave owners' actions (Exodus 21:20).
- Exodus 21:20 does mandate punishment for a master who kills a slave with a rod, but the very next verse says "But if the slave survives a day or two, there is no punishment; for the slave is the owner’s property" (NRSV). The NIV, by contrast, translates this verse as "if the slave recovers after a day or two", which changes its meaning. Either way, the emphasis is that the slave is first and foremost property, and therefore the greatest loss is to the owner, whose slave was "as good as money". 
Argument 4: "Slavery was allowed, but was not the ideal will of God."
- There are many ways a creative, all-knowing, and all-powerful deity could make it clear that slavery is immoral while, for instance, giving the Israelite economy a grace period to let slavery "wind down", should that be necessary. The passages concerning slavery from the Pentateuch (e.g. Exodus 21:2-7, Leviticus 25:44-46), by contrast, provide guidelines that allow for slavery to continue indefinitely. New Testament writers, too, who had an opportunity to overturn or clarify the Pentateuch's instructions, did not do so.
Argument 5: "The term 'slave' is a poor translation. It should be 'servant'."
- This may be plausible in some contexts, but not for Leviticus 25:46, which specifically allows that slaves are property who may be inherited by the owner's children and kept for life. This passage makes no sense unless they are discussing slavery—permanent ownership of one human by another—as we know it today.
- Jesus' parable of the unforgiving servant[wp] (Matthew 18:23) makes no sense if said "servant" is not a slave, since the master has the power to sell both the "servant", his wife and his children (Matthew 18:25).
- It also makes little sense in the case of Matthew 24:51 in which these "servants" may be not only beaten by their master (as in Luke 12:47), but that the master "shall cut him asunder" in the words of the King James translation.
 See also
- ↑ http://www.religioustolerance.org/reconstr.htm
- ↑ http://www.theologyonline.com/DEATH.HTML
- ↑ http://www.bibletrack.org/cgi-bin/bible.pl?mo=04&dy=13
- ↑ Note, however, that this doesn't actually prohibit any "just and fair" punishment of slaves
- ↑ By contrast, the NIV has the less accurate "slave traders", which makes it seem like Paul is condemning the slave trade in general - curiously, fundamentalists will sometimes prefer that translation of this one word, despite their general preference for the King James translation
- ↑ But it's interesting that Paul didn't try the para-sadism of Mother Teresa and her Orwellian "suffering for Jesus"-BS
- ↑ http://christianity.wikia.com/index.php?title=Atheism&oldid=14592#Atheists_may_say_the_Bible_is_morally_deficient
- ↑ http://www.gotquestions.org/Bible-slavery.html
- ↑ http://www.biblestudytools.com/commentaries/gills-exposition-of-the-bible/exodus-21-21.html