The following response to many of the arguments against Christianity is a refrain I hear often: They misinterpreted the bible. This is of course uttered by Christians explaining how fellow Christians have done things that are no longer acceptable, blatantly wrong or so absurd as to make all of Christianity look bad.
Christians quoted the bible and the concept of hell to justify the slaughter of millions of Native Americans. Christians used The Gospel of Mathew 27:25 to justify the blood libel and consequently kill upwards of 200,000 Jews. Women in the Church were oppressed and denied rights for most of Christianity's existence because of verses written by Saint Paul in The Book of Timothy. For 1500 years Christians thought that the Earth was the center of the Universe citing The Book of Genesis. In all of these cases present day Christians acknowledge that these past Christians were wrong but give the same explanation: Those Christians misinterpreted the Bible.
This response is supposed to tell us two things: One, that Christians no longer commit such acts of violence or stupidity, and two, that today's Christians somehow know better.
So did today's Christians receive some new divine revelation that was not given to previous Christians? Does this mean all Christians somehow know the true interpretation of the Bible and all the denominations can now be unified under one Church? No, this response doesn't mean either. What it means is that in the face of science and a more tolerant society, Christianity has had to re-interpret the Bible in order to maintain relevance. In addition, it tells us that the Bible does not contain any real truth, and whatever information it does contain is relative to person and epoch.
Facing the questions about the morality of hell, many Christians like Rob Bell have started to suggest that Hell might not exist after all (I strongly suggest you read this article to see just how divided Christianity is on this). Most Christians no longer agree with the interpretation in Timothy that says women should be submissive. Were these previous Christians misinterpreting the Bible for the past 2,000 years, and it was only recently that Christians received some divine revelation of the true interpretation? Or is it that our society has changed such that eternal torture and oppression of women is no longer acceptable, and the church has conveniently reinterpreted many of those verses to keep up with the times? The Church had to re-interpret and revise their stance on cosmology and human origins in the wake of Copernicus, Galileo and Darwin. Not only did they come to agree with Copernicus regarding the position of Earth in the Universe, they were arrogant enough to claim they knew this first by citing versus in Psalms and Ecclesiastes. Recently, the Catholic Church said it was open to the possibility of evolution where before they were adamantly opposed to it. Christians killed hundreds of thousands of Jews throughout the centuries claiming that the Jews killed Jesus and cited Mathew 25:17 to justify it (this verse also laid the groundwork for the Holocaust). Of course today the practice of being able to murder innocent people with no consequences is unacceptable, so nearly all Christians have conveniently re-interpreted that part of the Bible.
The examples above make Christians look foolish and ruthless, but the biggest problem they have by using this excuse of misinterpretation is that it reveals that the Bible contains no real truth at all. For the past 500 years the church has had no single coherent message. Why? Because they cannot agree on an interpretation of the Bible. Dozens of different denominations have been formed because of disagreement on this point. Even within these denominations (especially the Evangelical Church) the interpretations vary widely. So what claim to truth do Christians have? Can any one denomination let alone one individual claim that they know the correct interpretation? Or that someone else has misinterpreted the Bible? What authority do they have to claim this? I guarantee for every Christian that makes a claim of truth, I can find another Christian who interprets it differently, and will claim the first Christian is wrong. Any Christian who claims misinterpretation by past Christians is also contradicting millions of other Christians. Whose interpretation should we believe? Who is correct? The answer is no one's. Interpretation is relative to time, place and person. There is no such thing as misinterpretation, only interpretation. If Christians can't agree on one message of the Bible, then we have no choice but to reject it as false.
Not only is Christianity's claim to truth practically gone, but their claims to moral superiority and justice are gone. Now, Christians past, present and future must stand accountable for their crimes. Christianity can no longer hide behind the shallow defense of misinterpretation. This means that Hell, the common idea held by nearly all denominations, and the horrid idea of guilt by association, are things Christians need to explain and justify thoroughly. This means that the oppression of women and Jews is something that they need to answer for instead of using the excuse that for hundreds of years Christians were somehow misinterpreted the word of God. If they can't, then our only choice is to reject Christianity as a viable way to achieve a just and compassionate society. If Christians don't know truth or justice, then what do they know? Other religions and Atheists can only use history and the effect it has had on society to judge the validity of Christianity, not the Bible.