Beware of false prophets, who come to you in sheep's clothing, but inwardly are ravenous wolves.
You will know them by their fruits. Are grapes gathered from thorns, or figs from thistles?
So, every sound tree bears good fruit, but a bad tree bears evil fruit. A sound tree cannot bear evil fruit, nor can a bad tree bear good fruit.
Every tree that does not bear good fruit is cut down and thrown into the fire. Thus, you will know them by their fruits.
Josephus complained bitterly about people who called themselves 'prophets' during the build-up of the first Jewish Revolt against Rome; these would lead a group of people out into the wilderness, or up the Mount of Olives or Mt Gerizim (the Samaritan holy site) or across the Jordan, promising to lead them into a new Exodus in which the pagans would be driven out and Israel freed from slavery to them...
Josephus took a dim view of any popular movement, being an aristocrat from a prominent priestly family himself -- a man who seemingly failed to understand why the rebel groups he nominally commanded would want to burn the tax & debt records in any city they took. But these people and the tradition they came from did seem to be bad news, continually expecting God to confirm and follow their interpretations of Israel's prophesied destiny, according to schedules they calculated from diligent and wrong-headed attention to their scriptures -- and the result of their efforts was always violent repression by the Romans.
One such revolt is said to have left 2000 insurrectionists crucified along the road that passed by Nazareth about the time Jesus was born. No doubt he heard about it, many times, as he was growing up.
Does this passage apply to anyone in our current times? Few of us believe in prophets anymore, but we are offered a wide array of futurists, politicians, and people who interpret the Bible in much the same way that Judean revolutionaries once consulted it in search of 'the day and the hour' when God would finally do their will... instead of praying for a better sense of God's will.
And there are so very very many people -- who think they've figured out what evil needs to be perpetrated, in hopes some promised good will result...