Ideally the church is different. It is made up of people who are as varied as can be: rich and poor, learned and unlearned, practical and impractical, sophisticated and unsophisticated, aristocratic and plebeian, disciplined and flighty, intense and carefree, extrovert and introvert—and everything in between. The only thing that holds such people together is their shared allegiance to Jesus Christ, their devotion to him, stemming from his indescribable love for them.
That is why it is always wretchedly pathetic when a local church becomes a cauldron of resentments and nurtured bitterness. This pitiful state of affairs may erupt simply because there is very little at the social, economic, temperamental, educational, or other levels to hold people together. Therefore, when Christians lose sight of their first and primary allegiance, they will squabble. When social or racial or economic or temperamental uniformity seems more important than basking in the love of God in Christ Jesus, idolatry has reared its blasphemous head. When protestations of profound love for Jesus Christ are not mirrored in love for others who profess to love the same Jesus Christ, we may legitimately ask how seriously we should take these protestations.
D. A. Carson
A Call to Spiritual Reformation: Priorities from Paul and His Prayers