The Sermon on the Mount shows the ethics of Jesus, the way of how he wanted
his disciples to live. His kingdom of heaven or kingdom of God is now, in this time we live when each of us decides to obey what Jesus wants us to obey. Personally, what most impressed about the sermon of the mount is the amazing love the Son of God reveals here to man the will of His Father. Jesus had the only way to break standards that were created by man and to show love for others.
I think the Sermon on the Mount personally talk about many themes, but on this occasion, I would like to highlight how now speaks to us still with a loving, and authority voice. Jesus wants us to seek His Kingdom and to pray for its coming as our first priority in life. But we must have some sense of what will look like as it comes among us. At the same time, with what authority teaches us as well. He does not talk as the scribes, Not as Moses, not as Abraham. Or other. He speaks for who He is (the song of God)
To me, the primary message of this Manifesto is the way this message challenge my own life as a Christian. However it also helps me to be able to recognize the sense that the Kingdom of God has come, is coming, and is yet to come.