How do we know the teachings of Jesus in the Sermon on the Plain are true?

The Sermon on the Plain, recorded in Luke 6, presents Jesus's teachings as both an extension and a fulfillment of the law and the prophets. His authority is derived from His identity as the Messiah who came down to earth to deliver a clear message of grace and redemption. Jesus articulates principles that reflect the very nature of God's kingdom, showing the transformative work He brings in believers' lives. Additionally, the consistency and harmony of His teachings with the Old Testament scriptures, alongside their profound impact on the lives of those who embrace them, further validate their truthfulness. The historical context and allusions to Old Testament passages reinforce that these teachings are divinely appointed.