because he was teaching them like one who had authority, and not like their scribes.
Matthew 7:29 (CSB)
This is the last verse of the Sermon on the Mount, Jesus’ teaching in Matthew chapters 5 through 7. It explains why the crowds were so astonished: Jesus taught with authority, meaning the power and the right to command.
The scribes were the recognized experts in the law God gave through Moses. Many of them taught by quoting the respected teachers who came before them, but Jesus quoted no human teacher. Again and again in chapter 5, He said, “But I tell you,” and He expected His own word to settle the question.
Jesus could speak with that authority because He is not merely a great teacher. He is God the Son, who became a man without ceasing to be God. That is why His words are not one opinion among many, and why we ought to obey them even when they contradict what we would prefer.
At the end of Matthew, after His death and resurrection, Jesus announced, “All authority has been given to me in heaven and on earth” (Matthew 28:18). The One who holds all authority is the same One who died for our sins.
Everyone who trusts Jesus belongs to Him. And He has promised to be with His people always.