NT Church - All true believers are welcomed into the fellowship.

For by one Spirit are we all baptized into one body, whether we be Jews
or Gentiles, whether we be bond or free; and have been all made to drink into one
....Endeavoring to keep the unity of the Spirit in the bond of peace. There is one body,
and one Spirit, even as ye are called in one hope of your calling (1 Cor. 12:13; Eph.
4:3,4).

The practice of reception in the local church has been the source of
many divisions within the body of Christ. Throughout the history of the church, it has
often been necessary for true believers to leave the established church of their area
because of doctrinal error or the failure to judge immorality. On the other hand, many
local churches have split over issues that have been broadened beyond the intentions of
the Scriptures. One of the basic contentions through the centuries has been the reception
of believers into the fellowship of the church. Some local churches have no reception
policy, putting full responsibility upon the individual. This is one extreme which
eventually results in the local church being filled with unbelievers. Other local churches
have very strict reception policies which result in the local church becoming a sectarian
body that excludes true members of the true universal church of Christ. This is an extreme
in the other direction. The verses above would indicate that every believer in Christ is a
part of His body and our fellowship ought to be opened to all those who belong to His
body. Obviously, we cannot read the hearts; therefore we must accept the outward
confession. This outward confession must be questioned if the individual is in error
regarding the person and work of Christ. The daily walk also must be considered as
evidence of the confession. If the individual is practicing immorality in his life, his
confession of Christ is brought into question.

A distinguishing mark of a New Testament church is that it
receives all believers into the fellowship unless there are outward indications in word or
deed that their confession of Christ is doubtful.
Being in fellowship in a local
church is a term that is often not understood today. The term is used for the first time
in the New Testament in Acts 2:42: "And they continued steadfastly in the
apostles’ doctrine and fellowship, and in breaking of bread, and in prayers".
The word itself implies "sharing in common". In many local churches one
maintains his "membership" (a term not recognized in the New Testament) by
contributing financially to the church and attending occasionally or spasmodically the
"services" of the church. This kind of "attendance" only at the local
church can hardly be construed as fellowship in the New Testament usage of the word.
Fellowship not only involves sharing time and concern with one another, but also loving
one another. "If we love one another, God dwelleth in us, and His love is perfected
in us" (1 Jn. 4:12). We want to share our lives with those we love. True fellowship
also involves our behavior and walk. It implies that we have willingly put ourselves under
the discipline of the local church. "Obey them that have the rule over you, and
submit yourselves; for they watch for your souls, as they that must give
account....." (Heb. 13:17).

The questions then to be asked in looking for a New Testament church
are: Does the church have a reception policy or does it permit anyone to be in fellowship
without any inquiry or visitation? Has the church instituted requirements that forbid true
believers in Christ from the fellowship of the church? In answering the second question,
it is necessary to understand that certain limitations by the elders may be practiced
through years of practical experience. The interpretation of what constitutes a "true
believer" according to Scripture may vary to some degree from place to place. For
example, baptism does not make one a true believer nor does the lack of baptism prevent
one from being a true believer. But the question might be raised, why would a true
believer not want to be baptized after he is taught the truth of baptism? Another example
might be, if a "believer" keeps jumping from one church to another, would it be
wrong to investigate the cause for his frequent changes? Thus it becomes important to know
that the local church has a reception policy and to know that the practices of that policy
do not exclude the reception of true believers into fellowship.