Our highly independent nature makes it difficult to compile accurate statistics on congregations of the Church of Christ. Mac Lynn seriously attempts such compilations. I wish to use his most recent publication to illustrate a New Testament fact.
We have just over 13,000 congregations in the USA and its territories. Of those, about 3,275 do not consider themselves in fellowship with other congregations. The average size of a "mainstream" congregation is 112 members. Total membership in the 13,198 congregations is just over 1,276,500 people.
Do the math. In our USA membership of 1,276,500, between 20 and 25% of our members reject other baptized believers. Our USA population is approximately 291,191,592. Our world population is approximately 6,297,988,273. To regard ourselves as a major influence on religious thought may be more a matter of arrogance than reality.
Personally, I doubt that we understand the complexity of the early church. We have begun to realize that the mindset of Christian Jews in Palestine and Christian Jews in other regions differed significantly. We still need to realize the complex differences between (a) Jewish Christians who had God's scriptures for generations and (b) Christians whose families worshipped idols for generations.
We do not deal well with the fact that most [if not all] Christians in the New Testament were first generation Christians. Their homes of origin were not Christian homes. Our naïve concept: if we worshipped with Jewish Christians in Palestine, worshipped with Jewish Christians in Galatia, and worshipped with non-Jewish Christians in Corinth, each would do exactly the same things in exactly the same ways. We are slow to realize many epistles addressed those differences for the sake of encouraging acceptance, not for the sake of demanding conformity.
Paul did not commend the group in Corinth who sustained division and said, "I am of Christ" (1 Corinthians 1:10-17). He did say this to the seriously divided Christians in Rome: "Who are you to judge the servant of another? To his own master he stands or falls; and he will stand, for the Lord is able to make him stand" (Romans 14:4).
The master is Jesus. Jesus understands acts of faith coming from the heart. Even if one believer is a vegetarian for faith reasons while another believer for faith reasons eats food sacrificed to an idol; even if one believer keeps holy days to honor God while another believer rejects holy days to honor God, Jesus the master understood. He knew the "why" and caused each to stand.
Being different is okay. Being faithless is not okay. Trusting Jesus Christ is essential.
Link to other Writings of David Chadwell