And immediately there was in their synagogue a man with an unclean spirit. And he cried out, “What have you to do with us, Jesus of Nazareth? Have you come to destroy us? I know who you are—the Holy One of God.” But Jesus rebuked him, , “Be silent, and come out of him!” And the unclean spirit, convulsing him and crying out with a loud voice, came out of him. (Mark 1:23-26 ESV)
Jesus taught with authority since he is from God and is God himself, his teaching wasn’t based on someone else’s power or teaching, and this is validated that even his words can drive evil spirits out. And sure enough the Unclean spirit actually claimed who Jesus is! The holy one of God! Though this is not the time for Jesus to reveal who he is yet, the people around him can surely still see what Jesus can do :)