Christian morality changes over time and is interpreted differently by different Christian sects. Individual Christians disagree among each other over what they think is God's moral law. Many Christians have a tendency to idealize victimhood. The popular film, "The Passion of the Christ" shows this. Further, the popularity of the story of Noah's flood suggests something potentially evil. Christians believe they base their morality on what they think God wants, on trying to imitate God and Jesus. Some Christians are adept at finding Bible-based excuses for what they personally want to do; such as slavery and capital punishment - or emancipation and repentance, the bible can be made to support whatever you want.
Christian and humanist morality compared
If you are an atheist, agnostic or another person who doesn't accept any particular religion you almost certainly also want to be moral. Your self-respect is better if you are a moral humanist and other people will respect you as well. Humanist morality improves conditions in this world which is the only world we know exists.
Far too many Christians assume that atheists can’t be moral or are morally defective. After a former Christian deconverts, long-standing Christian friends or family members occasionally decide without reason the former Christian isn’t moral anymore. Here’s a recent example. It’s not a particularly bad example. It’s an example from a thread which happened to be active in August 2008 when this was written.
The main part of the discussion was focused on faith. Not just his faith, but what have I put my faith in. How do I know what is wrong or right... mainly in the context of my personal morality. What do I do when I am alone. Why not lie? Why not steal? I mentioned that it makes sense to me that morality could evolve in a communal setting, but he honed in on personal morality again. He said now that I don't believe in any religion, what is my construct in the way I behave? I have to admit that I don't have the best answers to this question. I treat people with respect and kindness. I don't lie (except those little lies like, "Yes, honey. You look fine." But, heck, I almost never even do that.) Basically, I really do live the Golden Rule, but this had no persuasion on my friend since that doesn't deal with what I'd do when I'm by myself. 
In the above case the Christian’s long standing knowledge of how his friend behaves was discounted. Since the atheist had deconverted it was assumed that he can’t be moral any more. There are serious problems for atheists for example in the more intolerant parts of the United States Bible Belt especially in rural areas. Fundamentalist Christians worldwide are cult-like and sometimes out of touch with reality. “What the Bible Says” counts for more than direct observation. The pastor chooses which parts of the Bible he wants his flock to read and interprets it for them. When Christian morality is examined thoroughly it becomes clear that Christians have no good reason to feel superior.
Cult like Christians being uncharitable
How a Baptist Minister behaved:
My wife is an apostate. When she came clean about her doubts in religion to her baptist congregation, very few of them remained friends with her. Her former pastor told her she could no longer claim to be, or even use words like, 'good' and 'moral' because she had no foundation to give them without g-d. People she went to high school with and thought of as close friends ignore her attempts to contact them. And, of those who still talk to her, most of them think she's just going through some sort of phase and try to talk her into going to church with them when she visits (we've moved several hours away), which she doesn't seem to mind, but I take as very disrepectful of my wife's views. 
Fortunately only a minority of Western Christians are as extreme as the above example. Many of the more Liberal Christians would argue that the pastor described in the above text was being judgemental and unchristian. In some areas, for example parts of the United States Bible Belt far too many Christians assume that without their religion nobody can be moral. Some disregard the good life lived by, for example Mahatma Ghandi because he was a Hindu. Others assume some type of religious faith is required for a person to be moral. Naturally they provide no sound scientific or empirical evidence for this extreme claim. They refer to their unproved religious teachings. Psalms 14, 1 is often quoted as is Psalms 53, 1. The Psalms were written by the same Bronze Age herders who thought children who made fun of a prophet deserved death as shown in the next section.
According to the Old Testament (2 Kings 2:23 & 2:24) God sent two she-bears to tear some children to pieces because they made fun of Elisha’s bald head.  Children can be really thoughtless and cruel when they make fun of people. Bad-tempered people can easily be tempted to curse them. Nonetheless that behaviour in a child cannot merit the death penalty in any civilized country. Indeed any mass murderer who caused forty children to be killed in that horrific way would certainly face life imprisonment without parole in any civilized country. Bronze Age herders wrote that part of the Bible and those teachings are totally unfit for the 21st Century. Throughout most of church history Christians believed this was literally true. Fundamentalist Christians still believe it today. Liberal Christians see the bad parts of the Old Testament as symbolic of something or other in some way or other.
The above is just one example among many of God as an arbitrary, capricious character corrupted by power. Fortunately most Christians ignore the worst aspects of their God’s alleged actions when deciding how to behave. Better Christians also ignore the worse behaviour of God's so-called representatives or prophets. The better Christians decide which parts of their alleged God’s behaviour are worth imitating by following their intuitive sense of right and wrong. The bad parts of their God’s behaviour are explained away or ignored.
Atheists also have an intuitive moral sense. Part of this intuitive sense is hard wired into human brains. That part is the same across cultures and religions and among those without religion. Another part of the intuitive sense of right and wrong is culturally determined. That part varies between cultures, between religions and at different times in history. It varies among Christians as well as among atheists.
So-called timeless morality
Christians enjoy the fiction that they have a “timeless” morality set in the Bible. In reality Christian morality changes over time as does other morality. A glance a history shows this and slavery is a good example.
Christianity and Slavery
Before the American Civil War slave owners in the South of the United States used passages in the Old Testament and the New Testament to justify their position. The Bible even permits beating a slave to death with a reservation.
21:20 And if a man smite his servant, or his maid, with a rod, and he die under his hand; he shall be surely punished.
Exodus 21:21 Notwithstanding, if he continue a day or two, he shall not be punished: for he is his money.
If a master beats a slave to death the master will be punished provided the slave dies at once. If the slave survives and suffers for a day or two before dying the master is not punished. He only loses his property.
St.Paul in the New Testament also sanctions slavery. This comes in Ephesians 6.
6:5 Servants, be obedient to them that are your masters according to the flesh, with fear and trembling, in singleness of your heart, as unto Christ;
6:6 Not with eyeservice, as menpleasers; but as the servants of Christ, doing the will of God from the heart;
Masters are told to treat slaves well though it’s still OK to give slaves reason to be really frightened and tremble.
Today most Christians prefer to avoid those 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 would say are evil.
Below is a Christian attempt to justify slavery written as recently as 2008.
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.
Church based morality
All Christians believe that the Bible is authoritative to varying extents. All Christian sects have their own unique way of interpreting the Bible which their leaders teach to the faithful.
Additionally the Roman Catholic Church believes that the Pope’s statements and the churches teachings are sometimes binding on the faithful. For centuries the Roman Catholic Church overlooked scandalous child sex abuse among the clergy. A Roman Catholic priest sometimes acts as a normal man, falls in love with an adult woman and marries her. He has to leave the priesthood. He is further told that his marriage is invalid. He is in mortal sin and in danger of Hell while he remains with his wife. He and his wife are both considered in mortal sin and they should escape damnation by separating. By contrast a priest who abused little boys and/or girls could and can confess, receive absolution and continue as a priest. If child abuse by a particular priest became scandalous he would be moved to a different parish where parents did not know that they needed to protect their children from him. The Roman Catholics claim they've have reformed but we won't know till the present generation of Roman Catholic children are adult and can complain about any abuse.
With this record the Roman Catholic Church believes that it has the authority to teach what is right and what is wrong. They try to teach their own membership and to the whole world.
- Criticism of Christian Morality
- Atheist Theft of Christian Morality
- Humanist morality Atheism Wiki has a better alternative to Christian morality.