The words “all that I commanded you” (Matt 28:20) describe the substance of what Christian disciples are to teach in fulfilling Christ’s Great Commission. Since Jesus in the progress of His earthly ministry changed focus in response to Israel’s opposition to Him as their Messiah, understanding what disciples are to teach requires interpretive discernment regarding the historical and theological background of His various utterances. As a sample of His teaching, the Sermon on the Mount is appropriate. The Sermon came in the historical circumstances of Jesus’ emphasis on the coming kingdom promised to David in the OT, and lays down prerequisites for those who want to enter that kingdom. Qualities expressed in the beatitudes enumerate those prerequisites. One in particular in Matt 5:5b promises the privilege of inheriting the land promised to Abraham in Gen 12:7. The Sermon’s theme verse, Matt 5:20, is a rebuke to the scribes and Pharisees who so strongly opposed Jesus during His time on earth. The antitheses that follow in Matt 5:21-48 are corrections to their superficial rabbinic interpretations of the OT. In line with keeping the historical context in view, the term “brother” in the Sermon refers to fellow Israelites, not Christian brothers. Failure to interpret Christ’s instructions properly leads to impediments that hinder fulfillment of the Great Commission.