Rather than summarize each aspect of the Sermon on the Mount, we're just going to look at the main sections of it
v1-2 - INTRODUCTION
It's not likely that this sermon was preached to a large audience. Notice the opening line: Jesus saw the crowd, but instead of addressing them, Jesus takes His disciples up into the hills.
This amazing sermon is not for everyone. It's just for followers of Jesus.
v3-12 - BE HAPPY
We often summarize the ten commandments as 'Thou shalt not...'. We tend to think of God's rules as things that keep us from doing what we want; things that keep us from having fun. But even those ten rules were given "so that you may live long in the land the Lord your God is giving you."
The Beatitudes are given in that same vein. Although it seems sputten (even if you don't know this Dutch word, you can figure it out from the context), Jesus' commands could very literally be translated as 'Happy are those who...".
Blessed people are those who
have everything they need and are content.
are living in a condition the Old Testament refers to as Shalom.
As evidenced by the 10 Commandments in the Old Testament, and the Beatitudes in the New Testament, God wants you to be happy!
But just look at how counter cultural both the Commandments and the Beatitudes are!
v13-21 - YOUR IDENTITY
You are both salt and light,
created to fulfill God's commands (as summarized in the Ten Commandments and the Beatitudes).