Question;

Is the quality of the lives of believers sufficient evidence of the truth
of Christianity?

Answer:

I do not know what you mean by “sufficient evidence.” Sufficient to
whom? I know from experience that for some people, seeing the life of
Jesus Christ lived out in individual followers of Jesus is sufficient to
convince some people of Jesus and to become a Christian. I guess that for
such people, this evidence is sufficient for them to be saved.

Having said this, but not being sure exactly what you asking, I say the
answer is no. Generally, the evidence of a life of a single person
well-lived for Christ may be sufficient for some people to become a
Christian, but it is almost certainly not enough “evidence” to sustain
that faith for a lifetime. Besides, there are some people for whom the
evidence of the life of a believer is not particularly helpful. For some,
it is the evidence of miracles, or the evidence of the consistency of the
Bible, or the evidence of the fulfilled messianic prophecies. My personal
problem with using the life of an individual Christian as evidence is that
evidence is not a solid foundation to build upon. Jesus is. A Christian
who is doing well today may be struggling tomorrow. Besides, there are
many Mormons or Jehovah?s Witnesses who live fairly good “lives,” yet
believe blatantly false doctrine. If a non-Christian has a good life and
a strong belief, does this disprove Christianity? Many Muslims use the
lives of godly followers of Muhammad as “evidence” for Islam. For these
reasons, I strongly suggest that, although the evidence of our lives is
important, and for some people even crucial, we ought to build the faith
of believers on something deeper and more substantial than this.

John Oakes