Produce good fruit

Luke 3:1-14
The word of God came to John son of Zechariah in the wilderness.
He went into all the country around the Jordan, preaching a baptism of repentance for the forgiveness of sins.
"A voice of one calling in the wilderness, ‘Prepare the way for the Lord, make straight paths for him. Every valley shall be filled in, every mountain and hill made low. The crooked roads shall become straight, the rough ways smooth. And all people will see God’s salvation.’”
The ax is already at the root of the trees, and every tree that does not produce good fruit will be cut down and thrown into the fire. 
For I tell you that out of these stones God can raise up children for Abraham.
Which explain what it means to produce good fruit in keeping with repentance. occur only in Luke. Genuine repentance will show itself in daily life - in kindness, generosity, honesty. The soldiers are told, 'No bullying(欺凌); no blackmail, make do with your pay!'
Why?
John preaching a baptism of repentance for the forgiveness of sins after he got the word of God in wilderness.
John is preparing the way for the Lord, prepare the way of Jesus Christ.
Produce good fruit, if not will be cut even is son of Abraham, Ax is ready. Out of these stones God can raise up children for Abraham. Means not only Jews but foreigner could be son of Abraham.
How?
Confess our sins and repentance, it is the only way to come close the Lord.