The New Testament of Jesus teaches that all believers are to be unified. Jesus said, “I do not pray for these alone, but also for those who will believe in Me through their word; that they all may be one, as You, Father, are in Me, and I in You; that they also may be one in Us … And the glory which You gave Me I have given them, that they may be one just as We are one: I in them, and You in Me; that they may be made perfect in one …” (John 17:21-23). Thus, the Lord prayed for unity among all believers.
Denominationalism brings division between believers, not unity. Man- made names, such as Methodist, Baptist, Presbyterian, Episcopal, etc., divides those who accept and promote them from those who accept only what is found in the Bible. Individually, believers in the New Testament were called disciples, brethren or Christians (Acts 20:7; 15:3; 11:26).
Collectively they were called the church of God, the body of Christ, the house of God or the church of Christ (1 Corinthians 1:2; Romans 12:5; 1 Timothy 3:15; Romans 16:16). How can God approve of man-made names that bring division among believers?
Further, the New Testament teaches there is one church. Paul said Jesus was the head of the body, the church (Ephesians 1:22-23). He later wrote there is by one body (Ephesians 4:4). That is, there is one universal body of believers. The Bible also reveals various local congregations of believers, Corinth, Ephesus, Thessalonica, Philippi, etc.
Never is there found any group larger than the local church, but smaller than the universal church. Yet, denominations are larger than a local church, but say they are smaller than the universal church. They say they are a part of the body of Christ. Their claims go directly against the teaching of the Holy Spirit. So, how can God approve of them?