The central message of this sermon is that the authority with which Jesus speaks is not just about the content of his teachings, but about who he is as a person. The speaker emphasizes that Jesus' words are not just moral teachings, but expressions of his own divine nature and power. This means that in order to truly live by the Sermon on the Mount, one must submit to Jesus' authority and acknowledge him as Lord and God. The sermon advances the belief that true morality and righteousness come from a personal relationship with Jesus Christ, rather than just following moral teachings or principles. The takeaway is that mere intellectual understanding or moral behavior without a deep commitment to Jesus' authority and lordship will ultimately fall short of true spiritual transformation.