The crowds were amazed at his teaching, because he taught as one who had authority

 Matthew 7:13-29

Watch out for false prophets. They come to you in sheep’s clothing, but inwardly they are ferocious wolves. Every tree that does not bear good fruit is cut down and thrown into the fire. Thus, by their fruit you will recognize them.

Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only the one who does the will of my Father who is in heaven.

Therefore everyone who hears these words of mine and puts them into practice is like a wise man who built his house on the rock. 

When Jesus had finished saying these things, the crowds were amazed at his teaching, because he taught as one who had authority, and not as their teachers of the law.

Make sure you are on the right road to eternal life.

Beware of being misled - tell true from false 'by their fruits'

Words are not enough; many are self-deceived.

The safe course is to act on Christ's teaching: a house built on rock can stand the storm

The  'sermon' over, Matthew notes the authority that set Jesus apart from all other teachers and impresses his hearers.

Why?

Jesus is the son of the Lord, so his teaching has authority.

Practice the word of Jesus in action is a wise man who built his house on the rock. When doing it, then it can stand under the storm.

Watch out the false prophets, we can not identify them from outside, but we can identify them by their fruit.

How?

Listen to the word of God and practice it in my daily life.