I am firmly convinced that the biggest factor in determining our actions is the story that we tell ourselves. If one is a Christian, how we read the story of the Bible determines our actions.
It is not the specific commandments of the Bible that are determinative, but the story. Stories shape our self understanding at such a deep level that this is what informs our attitudes, outlooks, and behaviors.
I think that much of what goes on in the name of Christianity comes from a fundamental flaw in our reading the Christian story. It has to do specifically with a misreading of the character of God as revealed in Jesus. This misunderstanding comes at the climax of the biblical narrative, the death of Jesus on the cross. You see, if one reads the death of Jesus on the cross as simply a placeholder until Jesus returns to bring judgment and wrath on God's enemies, then one can justify killing in the name of God. If Jesus' death on the cross was only the temporary solution to sin until he could come back in power, wrath, and judgment, smiting all of God's enemies, then Christians can claim to be agents of that judgment in the here and now.
But, if you read Jesus' death on the cross not as some placeholder, not as some temporary dealing with individual sins, but rather as God's answer to a wicked world, God's message that power comes through weakness and surrender, then the whole justification for carrying out God's wrath falls apart. If Christians are truly to live out WWJD, the answer always comes back, love your enemies and take up your cross.
This misunderstanding I think gets put on full display in many readings of the parable of the pounds in Luke 19:11-27. In that parable, a nobleman goes away to receive royal power and leaves his possessions in the hands of his slaves to do business with. His citizens oppose his rule, and send a delegation after him argue against his becoming king. The nobleman receives his kingdom, returns and calls his slaves to account. He rewards those who made money and takes away everything from the slave who made nothing. Finally, he slaughters those citizens who opposed him. The misunderstanding in many readings of this parable is to think that the nobleman is Jesus. But, if one reads this parable in the light of its historical background, it is impossible to think that this nobleman is Jesus. Instead, Jesus is describing the story of Archelaus, son of Herod the Great, an especially hated king. Archelaus had to travel to Rome to have his kingship ratified by the emperor. His citizens opposed him and sent a delegation after him to oppose his kingship to the emperor. He did receive part of his fathers kingdom and ruled for ten years. On multiple occasions he slaughtered citizens who opposed him. Jesus, in the parable of the pounds is describing Archelaus, not himself. He is describing earthly kings with their lust for money and power. He is not describing himself or the Kingdom of God. Yet, largely because of Matthew's similar parable of the talents, many read Luke's parable of the pounds as the story of Jesus as King. If that happens, then Jesus is a king who is going away for a time, but will one day return to smite his enemies. If that is the case, then Christians, who are of course on Jesus' side, can happily go along identifying Jesus' enemies and smiting them as they have the opportunity, all in Jesus' name.
I have come to read the story differently. Jesus' death on the cross was God's answer to the violence of the world. The answer to violence, hatred, and wrath is not to fight it with more violence, hatred and wrath, but rather to submit in love and service. Here is how Jesus put it in Mark 10:42-45:
42 So Jesus called them and said to them, “You know that among the Gentiles those whom they recognize as their rulers lord it over them, and their great ones are tyrants over them. 43 But it is not so among you; but whoever wishes to become great among you must be your servant, 44 and whoever wishes to be first among you must be slave of all. 45 For the Son of Man came not to be served but to serve, and to give his life a ransom for many.”What do you think?