NOTE: This was part of an answer to a question I had, but there is some parts which make a good study.
The portion I quoted was from Jesus' "sermon on the mount", found in Matt chapters 5-7. The point I was attempting
to make is that the fruits spoken of is the 'deeds', or 'works' of the persons Jesus was referring to.
If you are observant of the gospel accounts of Jesus' ministry, you will realize that the persons who hated
and ultimately killed Jesus were the 'preachers' and 'priests' of the various denominations of the day, the Saducees, the
Pharisees, the Essenes, the Herodians, as well as possibly others. The ordinary people, on the other hand, loved Jesus and
believed He was from God, because of the miracles He performed for them. It was, ironically, (tho prophesied) the so-called
'church' which killed Him.
The Word (in Proverbs, Acts and Romans) states that there is nothing new, and that our God is the same forever.
Thus, today we have hundreds of 'denominations' and 'churches' which continue daily to 'kill' Jesus and His Word many times
over with their rules and traditions, which are not at all scriptural, but are just 'church' traditions, much like the traditions
posessed by the "church" which crucified Him originally.
If you are truly interested in finding out about the tares Jesus was referring to, you must realize who they
were and are. Yes ARE. they are still here. Have you ever heard of the Kenites? In Rev 2:9 and 3:9, they are identified as
"those who claim to be of Judah, but are both liars and the synagogue of Satan." Thus these are not physical liars, murderers,
and adulterers, "sinners", but SPIRITUAL liars, murderers and adulterers. You can find these kenites in Genesis, Exodus,Numbers,
Joshua, 2 Chronicles, Judges, Ezra, Jeremiah and Isaiah. They were the ones who had taken over the 'church' when Jesus came.
He Identified them very well in John 8:44. Even a child can understand those words. They (the Kenites) have nearly suceeded
in completing their one world system at this present time (Daniel 7-12). They call it the New World Order. Perhaps you have
heard the term.
It is described quite well in several chapters of Isaiah, Joel, Daniel and Revelation. Thus to "know them
by their fruits", means that you must judge God's teachers and people not by 'denominational' teachings or traditions, but
only by the written Word of God which we have. You must somehow determine the true meaning of the written Word. This is the
Believe it or not, YOU MUST do this all by yourself. Do NOT take ANY man's word for what God's Word means,
and ESPECIALLY do not believe ANY church's teaching without checking it out in the Word for yourself.
There are only two spiritual prerequisites for you to study on your own.
1) You must believe ALL of God's Word is true, as written.(PS 25:5, JN 17:17)
2) You must be willing to change any notions you may have been taught by man, and allow the Holy Spirit to
guide you into all truth. (Luke 12:2, Jn 16:13)
There are also two physical prerequisites.
1) A King James version Bible, and
2) A Strong's Exhaustive concordance with the Hebrew and Greek dictionaries.
Handy, though not absolutely necessary, is a copy of Green's Interlinear Bible (original texts) with Hebrew
Greek and English translations. You will be absolutey amazed how God's Word comes alive when you trace the english words to
their original language roots and meanings.
Two words of warning are next.
1) Don't expect your preacher to accept the little pearls of truth you are going to find. He will ridicule
you for them. (Mt 7:6)
2) Don't expect to find many people to exchange ideas with. There are many who believe in God, there just
aren't many who believe God's Word. They are more comfortable with 'church' traditions. (Jn 15:17-18 and Mt 15:1-9)
God is calling out His own in these times. Some will have a lot of work to do before long.