19 I will personally deal with anyone who will not listen to the messages the prophet proclaims on my behalf.
21 “But you may wonder, ‘How will we know whether or not a prophecy is from the Lord?’ 22 If the prophet speaks in the Lord’s name but his prediction does not happen or come true, you will know that the Lord did not give that message. That prophet has spoken without my authority and need not be feared.”
Jesus was first reaching out to a man in need and then ridiculed by the religious for doing so on the Sabbath. He addressed them by sharing if they relied on the teaching of Moses, they should know He was coming and they should recognize He was doing the work of, and being led by, God.
God said He would do something and He did. He came to save the world and empower everyone with His Spirit. He did so, so we would walk out His will and others who need Him would recognize Him in His believers, compelling them to call out to Him for salvation.