According to the Bible, the Sermon on the Mount was a speech that Jesus of Nazareth gave to his followers and a large group of people around AD 30. Jesus gave the speech on the side of a mountain. The most popular part of the speech is the Beatitudes, which are at the beginning. The Sermon also contains the Lord's Prayer. Other popular lines from the Sermon on the Mount are "turn the other cheek," "salt of the Earth," "light of the world," and "judge not, that ye be not judged." 

Many Christians believe the Sermon on the Mount is related to the Ten Commandments. They believe that both are very important in explaining how Christians should act towards others.  In choosing the mountain as the setting for this sermon, Jesus may have meant to show how His teachings were similar to those of Moses who brought the Ten Commandments down from Mount Sinai.

Beliefs about the Sermon's meaning 

One of the most important debates over the sermon is how it should be applied to everyday life.  Almost all Christian groups have created their own ways to understand and use the Sermon in their lives. In a book called Understanding the Sermon on the Mount, Harvey McArthur lists twelve different views about the Sermon.

(1) The absolutist view 
The absolutist view says that people should do exactly what Jesus said in the Sermon, all the time. If doing this puts a person in danger, then that is what the person needs to be saved. 

People who believed this included:
 St. Francis of Assisi
 Dietrich Bonhoeffer
 Leo Tolstoy (when he was older)
Churches which believe this view include:
 The Oriental Orthodox Churches
 The early Anabaptists
 Modern Anabaptist groups, like the Mennonites and Hutterites

(2) Modify the text 
In ancient times, people would modify (change) the text of the Sermon to make it more popular. For example, in the Bible, Matthew 5:22 was changed from "[anyone who] is angry with his brother shall be in danger of the judgment" to "[anyone who] is angry with his brother without a cause shall be in danger of the judgment."  

In recent centuries, it has been more common to change the words in the Sermon, to take out parts that people would have trouble accepting.

Almost every major Christian writer has made changes like this at some point.

This view is not supported by any specific Christian denomination.

(3) The hyperbole view 
One of the most common views is the hyperbole view.  It says that Jesus used hyperbole (which means he exaggerated) in parts of the Sermon. People who believe this think Jesus's teachings need to be made more realistic if they are going to be used in the real world. 

Most people agree that there is some hyperbole in the Sermon, but they argue about which parts are hyperbole.

(4) The general principles view 
The general principles view says that Jesus was not giving instructions (telling people exactly how to act). Instead, he was giving examples of how a person should behave.

(5) The double standard view 
The double standard view says that part of Jesus's teachings are general ideas about how to act, and some are instructions. To be saved, most people just have to follow the general ideas about how to act.  Only a small number of holy people, like the clergy and monks, have to follow the instructions.

People who believed this view included:
 St. Augustine (he created the double standard view)
 St. Thomas Aquinas (who changed the double standard view later)
 Geoffrey Chaucer (he used this view in his book, Canterbury Tales (Wife of Bath's Prologue, v. 117-118)
The Roman Catholic Church believes in the double standard view.

(6) The two realms view 
Martin Luther did not believe the Catholic ideas about the Sermon. He created the two realms view. Luther divided the world into two realms, or sections: the religious realm, and the secular (non-religious) realm. He thought the Sermon only applied to the religious part of life. In the everyday world, people might have to do things the Sermon said they should not do. For example, in his secular job, a judge might have to punish a criminal instead of forgiving him. However, as a religious man, the judge should still feel sorry for what happens to the criminal.

(7) The analogy of scripture view 
The analogy of scripture view says that when the New Testament was written, parts of the Sermon got changed.  For example, Jesus said that it was wrong to make an oath. However, in the New Testament, Paul uses oaths at least twice.

(8) The attitudes not acts view 
The attitudes not acts view says that in the Sermon, Jesus was only telling people what he would do himself. He was not telling other people what they had to do to be good Christians.

Wilhelm Hermann created this view in the nineteenth century.

(9) The interim ethic view 
The [wikt:interim interim] ethic view says that when Jesus gave the Sermon, he thought the world was going to end very soon. Because of this, his teachings were only meant for that short time.

Albert Schweitzer created this view.

(10) The unconditional divine will view 
The unconditional divine will view says that Jesus meant for people to do exactly what he said and follow the ethics he talked about in the Sermon. However, with the way the world is now, people cannot do this. People try to follow the ethics from the Sermon, but they will always fail. This will change when the Kingdom of Heaven comes back to the world. At that time everyone will be able to live the way God wants.

Martin Sibelius, a German philosopher, created this view in the twentieth century.

(11) The repentance view 
The repentance view says that Jesus knew people would not be able to follow his teachings. People would try to follow them, but fail. This would teach them to repent. In this way, people would come to have faith in the Gospel.

(12) Dispensationalism 
Dispensationalism divides human history into separate groups. This view says that today, we live in a time where we cannot live up to the Sermon's teachings. However, sometime in the future, we will be able to. When that time comes, people will have to follow the Sermon's teachings to get salvation.

Other views 
E. Earle Ellis, a professor of theology, says that in the Sermon, Jesus is asking believers to live in a way that will be normal in the future kingdom of God.  As Ellis says, we are to speak Jesus' words, think his thoughts, and do his deeds.  Since this will be the ethic of the future kingdom of God, people should live their lives in a way that will help them be ready to live in God's kingdom.

In a book called Hiram Key, Christopher Knight and Robert Lomas say the Sermon on the Mount never happened. Knight thinks that Matthew 'stuck all kinds of passages together as though they were spoken one after another to a crowd on a mountain top.' He believes that 'the teachings were drafted into this one 'occasion' to avoid interrupting the flow of the overall story.'

References 
 McArthur, Harvey King. Understanding the Sermon on the Mount. Westport: Greenwood Press, 1978.

Speeches
Jesus Christ
Gospels