See Poole on "Matthew 3:7", and following verses to Matthew 3:10, where we met with all this with no alteration, save that Matthew saith that he spoke this to the Pharisees and Sadducees, seeing them come to his baptism: though he did especially intend them, yet he spake in the hearing of the multitude, amongst whom they were.
Related Commentaries of Luke 3:9
Luke 3:9
9 And now also the axe is laid unto the root of the trees: every tree therefore which bringeth not forth good fruit is hewn down, and cast into the fire.