They were amazed at his teaching, because his words had authority.

Luke 4

They were amazed at his teaching, because his words had authority. v32

What are people amazed at - they are amazed because Jesus speaks truth - He says what the bible says... 

After He is baptized, earlier in chapter 4, Jesus beat Satan because of His use of scripture...scripture has power.  He then went on to Nazareth - His hometown, and quoted Isaiah, and again people were amazed...scripture has power:

All spoke well of him and were amazed at the gracious words that came from his lips. Luke 4:22

Scripture has power but sometimes people are confronted by this power because it shines a light on their own lives - see Matthew 8:

Some distance from them a large herd of pigs was feeding. The demons begged Jesus, “If you drive us out, send us into the herd of pigs.”

 

He said to them, “Go!” So they came out and went into the pigs, and the whole herd rushed down the steep bank into the lake and died in the water. Those tending the pigs ran off, went into the town and reported all this, including what had happened to the demon-possessed men. Then the whole town went out to meet Jesus. And when they saw him, they pleaded with him to leave their region.  Matthew 8:30-34

My Prayer: Lord, I know scripture has power - this is because it is You and You are powerful.  Yet I don't have enough knowledge and faith in Your word because I worry too much.  Thank You that You love me anyway but please forgive me Jesus.  Help me be the man You intend for me.  Help me turn from my worry.  Help me more fully devote myself to Your word so that I may have greater faith in You and Your power.  Help me love You with all of my heart, soul, mind and strength.