"When Jesus had finished saying these things the crowds were astonished at his teaching, because he was teaching them like one who had authority, and not like their scribes" (7:28-29).
He sure did!! I smiled when I read that verse because I had, myself, noticed how he had been talking! I never made a mental note of this before- but this time it stood out to me that he was saying, "Many will say to me on that day, "Lord, Lord did we not prophesy in your name..?" (7:22) , "Then I will tell them plainly, "I never knew you," (7:23) and "Therefore everyone who hears these words of mine and puts them into practice..." (7:24)
"To me", "mine", "I will"....Jesus isn't establishing his authority, he is already in charge!! I forget, when I read these verses, since I already know he has risen from the dead and is sitting at the right hand of God (Rom. 8:34) that these people had no understanding of all that.
Personally, I'm glad I am on this side of the story. As much as I would have loved being in the crowd, listening to Jesus myself....I might have had a hard time computing what he was saying about himself.
It just goes to show you, it doesn't matter what time period one is from... one needs faith to "get it". Abraham, before Jesus, needed faith to understand; these people in the audience needed faith to understand; we on this side (post the first coming of Jesus), need faith to understand. Faith is the key to understanding that Jesus is Lord and is in charge now! (John 8:24, Heb. 11:6)