People heard Jesus teaching and they said to one another that
'Here is a teaching that is new and with authority behind it'. V.27
They were able to make such a remark in comparison to what they had heard taught before from the teaching of the Scribes. They were very fond of legalistic teaching and were very strict in demanding observance of daily rules in detail. Jesus viewed the demand to keep rules in detail as imposing an unnecessary 'heavy burden' on people and the leaders themselves were above the rules. There was another kind of teaching that drew large crowds and that the crowds were happy to listen to and that was he teaching of John the Baptist who called for repentance to avoid God's wrath and the threats of punishment. 'Repent and believe in the Good News' is the message Jesus taught. There was no threat of punishment.
The teaching of Jesus was new because his teaching was drawn from his personal wisdom and knowledge about God and accompanied with miracles.
What is this wisdom that has been granted him and these miracles that are worked through him? Mk 6, 2.
The teaching was new because Jesus freed his hearers from the burden of observing their daily rules in detail and in doing so they were enslaved to the laws. The teaching of Jesus freed them and lightened their 'heavy burden'. His teaching opened their eyes and mind to see God in a new way. It helped them to see that God, whose love is much more powerful than their sins and whose mercy is boundless and whose compassion was for all. God's love and forgiveness is for everyone and there is no exception. Those who come to him would benefit from it.
The people also said Jesus taught with authority. What authority?
Jesus taught with authority because his view about God was so much different from the Scribes who disliked His teaching and wanted to arrest Him but they were unable to for fear of the crowds. The scribes' teaching authority depends on the traditional interpretation of the Torah and Jesus teaches with the authority of God (Mk 11:28-33). The scribes are bound to tradition and Jesus received power directly God the Father.
The unclean spirit cried out loud that 'I know who you are: the Holy One of God'. v.24
Jesus has authority over the unclean spirit. We noticed that for the man possessed by an unclean spirit, when Jesus gave a command and the unclean spirit left the man.
Jesus has the authority to calm the storm of the seas and the seas obeyed Him. Mk 4,35-41. There is another story revealing about the authority of Jesus where He says "the Son of Man has authority on earth to forgive sins 2,11". Jesus used his authority not to obtain power for himself but to serve humanity.