?

Why was 1 John 4:1-3 written?  Which people does he refer to who did not believe
Jesus came in the flesh?  If this was written in the first century, why would
anyone not believe that he came in the flesh with so many eye-witnesses still
alive?  Is it because they could not understand or believe God became man?

2nd question:

I am studying the Bible with someone and was wondering if it is necessary for
him to know before getting baptized who Jesus was in the sense of him being
the Son of God–God in the flesh?

            It is always hard to say for sure why someone did something, especially
when it was done two thousand years ago.  To some extent, one must speculate
about why John wrote what he wrote in this book.  From 1st John 4:1-3 we know
that there were people at the time the letter was written who were claiming that
Jesus was a spirit, but that he did not occupy a physical body.  Scholars will
tell you that the heretical group John is referring to is the Gnostics.  These
were a group who wanted to combine their Greek/pagan/mystery religion with Christian
thinking.  We know quite a bit about the Gnostics from their writings.  They
taught that Jesus did not dwell in a physical body.  They therefore denied the
physical death of Jesus on the cross.  You can see right away why John called
this group the Antichrist!

            Your second question is why people could believe such a heresy so
soon after the time that Jesus lived on the earth.  That is a good question. 
I believe that you can assume that  the eyewitnesses to the ministry of Jesus
were not among the members of the Gnostic sect.  The evidence is that these people
were not from a Jewish background at all, but that they were superimposing their
own Greek philosophy/religion on the Christian teachings.  These Gnostics were
very strongly opposed by the Christian church from the very beginning as you can see
from the book of First John.  In the end, as said before, it is hard to say
why a particular group from a long time ago did what it did, but it may help
for you to realize that these people were definitely not among the eye witnesses
to Jesus and that they probably had a very strong predisposition toward a particular
philosophy which was able, for them, to overwhelm the clear testimony of the
apostles and other eye-witnesses, few if any of whom they had met personally.

            On the second question, it seems clear from New Testament writings
such as 1 John that understanding who Jesus was is absolutely central to Christianity. 
It is my experience that before I or anyone I know baptizes anyone we ask them
to make some sort of confession such as, "Do you believe that Jesus is the Son of
God, that he lived on the earth, that he suffered and died for your sins." 
We do not have a particular formula, but tend to ask a question along these
lines.   I am not in a position to state unequivocably whether a person who is
baptized but did not understand who Jesus was is not saved, but I would be,
at the very least, concerned about that situation.  In your situation, with
the person you are studying with, this is not a problem.  You simply need to teach him/her
correctly.   If you have a situation in which you are concerned about someone’s
baptism based on their prior understanding of who Jesus is, I suggest you find
a local church leader whom you trust to share your concern.  It is not my position
to discuss individual cases of people I have never met.  Does this answer your
question?  Feel free to e-mail me directly.

John Oakes