Final answer:
Jesus' Sermon on the Mount is found in the Gospel of Matthew, specifically in chapters 5 to 7, which are part of the New Testament.
Step-by-step explanation:
The Gospel of Matthew, a cornerstone of the New Testament, houses the profound and transformative Sermon on the Mount, a compilation of Jesus Christ's teachings spanning chapters 5 to 7. Renowned for its ethical depth, the sermon encapsulates the essence of Jesus' moral guidance, covering topics such as the Beatitudes, love for enemies, prayer, and ethical conduct. Its enduring significance lies in its comprehensive elucidation of the Christian ethos, serving as a timeless guide for believers seeking spiritual enlightenment and ethical guidance in navigating the complexities of life.