I hope you realize the Sermon on the Mount isn't intended for everybody. It isn't written for everybody everywhere, whoever, wherever. Neither is it intended for people with a casual interest in God. It's meant for people who are interested and committed.
Outsiders are welcome to listen in.
But much of the Sermon on the Mount makes no sense unless you have decided to follow Jesus. It's a text for pilgrims, for people on a journey of faith. That's the only way I know for us to make sense of the text we've just heard. Jesus is preparing to give us a number of new commandments. And we are called upon to relate these commandments to the Jesus who gave them to us.