In the Sermon on the Mount Jesus doesn’t negate the command from Deuteronomy but pulls the teaching even deeper into a matter of the heart for all people. Jesus, in essence, is saying that God sees our hearts and if we have hatred in our hearts we are just as guilty of murder in the eyes of God. It isn’t just about our external practice or religion but it is about our purity of heart before the One who examines the heart and that is really the Heart of the Matter.