The Jews were trapped in a system of harsh legalism, where obedience was motivated by fear rather than love. The Pharisees made a grand display of holiness by keeping the law, but the Sermon on the Mount teaches that their hearts were empty. Jesus built on the Ten Commandments to create a system ruled by mercy, love and dedication to God. Even if the culture changes the basic ethical principles behind the sermon do not change. It is a moral code that focusses as much on inward moral disposition as it does our external actions: Jenkins wrote, inner attention and attitude is crucial.
Even if a typically good action is performed with sinful thought then it becomes immoral. The most important thing to realise about the Sermon on the Mount is that it is impossible for anyone to keep it completely, as it demands perfection. Although they will never be free from sin in this life, Christians use the sermon in order to try and become more like Jesus, who was perfect. The Sermon is all about Christian sanctification. Jesus speaks not only on what Christians should do to be moral, but he also explains why it is important to be ethical in the first place.
He states that Christians are the salt and light of the world. Salt is significant because it represents purity, preservation and flavour. Therefore we understand that Christians should maintain a good ethical code in order to set an example to society and to preserve it from total corruption. The image of the light is also key: in the Bible light always symbolises joy and blessing. A light is visible to all, and so the Christian should seek to make Christ visible to all through their actions.
A light is also a warning, representing the Christians duty to lovingly warn their fellow-men about their sin. Further on in the Sermon Jesus admonishes that, If the light then within you is darkness, how great is that darkness! Furthermore, the Sermon on the Mount gives many specific examples of Christian ethics, the first of which is regarding murder. Jesus equates anger to murder, and speaks of the fires of hell. This is contrary to the contemporary universalist view of Jesus and his death which has led some scholars to claim that when he speaks of hell it is merely metaphorical.
Regardless, Jesus is affirming that you cannot be right with God until you are right with your fellow men, which all relates to the salt-and-light reputation of a Christian. Jesus also teaches about adultery and sexual morality. Again he equates the inward sin of lust to the outward sin of adultery. He also declares that marrying a divorced woman counts as adultery, a part of the Sermon that even Christians have begun to disregard. This is contrary to the Old Testament where Moses permitted but did not command divorce due to the hard heartedness of the people.
The close relationship between a husband and wife mirrors the relationship Christ shares with his Church, which is why sex features so highly in Christian ethics. Love, when fully understood. Is opening oneself to another completely and can succeed only where trust and fidelity are present. Subsequently, another part of the Sermon on the Mount that is ethically significant would be where Jesus deals with how we should relate to other people. The standards set by Jesus are so high it is easy for Christians to look down upon those that are struggling.
Jesus, ever a carpenters son, uses the metaphor of the speck in your brothers eye and the plank in your own. We are all sinners and it would be highly hypocritical to judge another when we are also flawed. We never know the whole story about someone and it is impossible to be impartial in our judgement. The Jews were familiar with the concept of loving your neighbour and not judging him, but they did not feel the same about their enemies. Jesus commanded us to show agape love towards our enemies. Such love does not naturally come from the heart, but is instead must be put into action through ones own will.
As Jesus was merciful and forgiving to sinners, so we should be. This is vital to Christian ethics. Another ethical aspect of how we relate to other people is how we treat those who are poorer than us. It is not enough to simply preach to them, but we must take care of their physical needs as well as spiritual. Jesus said, Give to him who asks of you, and do not turn away from him who wants to borrow from you. Charitable giving was a fundamental part of Jewish life, but Jesus added another element: it was only ethical if done with the correct motivation.
The Greek word translated as hypocrite in the Bible literally means actor. This is why Jesus commands us to give in secret, lest we become boastful. Moreover, there is a definite eschatological aspect to the Sermon on the Mount as it draws to a conclusion. This emphasises to the Christian how their ethics are eternally significant and will be considered on the Day of Judgement. Jesus states that few will enter the Kingdom of Heaven and that not all that profess to believe in him as Lord will be saved.
He warns of false prophets who will come in sheeps clothing; in this situation the ethics presented in the Sermon on the Mount are vital so a Christian can identify who is a true believer. We are not saved by works, but they are an important part of our Christian identity. The Sermon on the Mount also has certain evangelical tones throughout. It shows the unbeliever what is required of them if they follow Jesus, and the severe consequences if they do not. Spurgeon wrote of this passage, The shepherd best discerns his own sheep, and the Lord, Himself alone knows infallibly them who are His.
To conclude, there are conflicting theories regarding the nature of the Sermon certain theologians such as Calvin believe it is a compilation of many separate sermons. Others debate technical details, such as whether it was preached on a mount or a plain. However, something that every Christian will agree on is that the Sermon on the Mount is of the upmost important as a foundation for Christian ethics. Stott said, The Sermon on the Mount is probably the best-known part of the teaching of Jesus, thought arguably it is the least understood, and certainly it is the least obeyed.