The Sermon on the Mount as Gospel
Matthew tells us that Jesus was traveling through Galilee, “teaching in their synagogues and heralding the good news of the kingdom” and that he was healing all diseases (4:23-25). Then he gives us the Sermon on the Mount (5-7), followed by a number of stories of healings (8-9). He wraps up this section with a summary statement, telling us that Jesus “went through all the towns and villages, teaching in their synagogues, heralding the good news of the kingdom, and healing every disease and sickness” (9:35, a clear echo of 4:23-25).
Since the summaries in 4:23-25 and 9:35 are identical and since what comes between them are a sermon and a bunch of healing stories and since the healing stories are obviously instances of the healings mentioned in the summary, we ought to see the Sermon on the Mount as an example of Jesus’ “teaching … and heralding the good news of the kingdom.”
So in the Sermon on the Mount, what is Jesus doing? He is heralding the good news of the kingdom.