Jesus gave the message from the mount, but the topic of the sermon is the Kingdom life. He speaks of the Kingdom in the very first verse. He is talking about the Kingdom in the last paragraphs. And in between he talks of it at crucial points throughout the message.
For many this sermon is foolish, unreasonable, idealistic and impractical, but that is because it is describing the life of these "aliens and strangers"from the future. These are Kingdom people who are living right now as though they were already in heaven or at least as though they are taking all their direction from heaven. They understand that their citizenship is really there.
This much is certain: Everyone who wants to be a disciple of Jesus must have a most eager heart when coming to this message. Every person who wants to live the Kingdom life must see the Sermon as "the Jesus Manifesto"and must want his or her attitudes toward everything to be shaped by what is said here in specifics or in principle.