authority

And they were astonished at His teaching, for He taught them as one having authority, and not as the scribes. Mark 1:22

Jesus was obviously not the first person to teach the scriptures, the people had heard many other teachers of the word of God. What set Jesus apart was that he spoke with authority. To many people taught what they thought with out being sure they taught theory not law. Jesus taught the LIVING words of God. When the teachers read Gods scripture and tried to come up with what it meant they came up empty but when Jesus taught God gave him full knowledge of his word.
That is why the teachers didn't like Jesus. Jesus made them look like trash and they didn't like that. Nobody wanted to listen to them anymore.
Jesus taught KNOWING what he was saying! God gave him the words he spoke.