It is important to emphasize biblical fundamentals, especially when they differ from contemporary religion. The churches of Christ belong to Jesus Christ, and consequently, they are obligated to conduct themselves according to what Jesus authorizes (Romans 16:16; Colossians 3:17). People living in the Gospel Age must heed the words of Jesus Christ rather than Moses or the Old Testament prophets (Matthew 17:1-5; John 12:48). Jesus Christ is the Lawgiver and Mediator of the New Testament, to which people living today must turn for religious instruction (James 4:12; Hebrews 9:15). Jesus Christ condemns alteration of the Gospel with "the commandments of men" (Matthew 15:9), and the apostle Paul condemned false Gospels and the human will when substituted for the divine will (Galatians 1:6-9; Colossians 2:23). One must turn exclusively to the New Testament to learn what God has authorized respecting Christianity.

There were no denominations in the first century to which the churches of Christ could have extended fellowship; Catholic and Protestant churches did not appear in history until several hundred years after the establishment of our Lord's church. It is true, though, that departures from primitive Christianity began in the first century, some of which doctrinal errors appear in the New Testament (e.g., 1 Corinthians). However, the Roman Catholic Church did not have a universally accepted pope until Boniface III in 606, and the Protestant Reformation Movement did not begin until 1517 when Martin Luther posted his 95 theses on the church door in Wittenberg, Germany.

In contradistinction, Jesus Christ established only one church over which he is the Head, and for which he will return someday. First, Jesus only promised to build one church, which belongs to him (Matthew 16:18). Jesus Christ is the only Head of his church (Ephesians 1:22; 5:23; Colossians 1:18). Jesus Christ is coming again to retrieve his church (John 14:1-3; 1 Thessalonians 4:16-17; 2 Thessalonians 2:1), not manmade churches, all of which came into existence centuries after our Lord established his church.

The churches of Christ (i.e., church of God, 1 Corinthians 1:2) are warned not to participate in religious division. The apostle Paul condemned religious division within a congregation, which principle also forbids participation in religious division (such as denominationalism) outside of a congregation (1 Corinthians 1:10-13). Christians are forbidden to participate with or fellowship anyone who does not continue in the doctrine of Jesus Christ (2 John 9-11). Instead of fellowshipping the doctrinally errant, faithful Christians are supposed to expose them (Ephesians 5:11 NKJV).

Further, each congregation of the churches of Christ is independent. No denominational headquarters with its organizational structure existed in the first century. There was no church government in the first century larger than each individual congregation. Each fully organized local congregation had its own elders who guided only the congregation over which they had been appointed (Acts 20:28; Philippians 1:1; Titus 1:5; 1 Peter 5:2).

In addition, churches of Christ fellowship each other based on their common regard for the authority of the Scriptures. True Christian fellowship exists between Christians and God plus between Christians and other Christians--all of whom have fellowship with God (1 John 1:3). Lacking the prerequisite of fellowship with God and not abiding in the doctrine of Christ, denominations are not suitable candidates for fellowship with the churches of Christ.

Denominations disregard the authority of the Scriptures in a number of ways, which makes it impossible for the churches of Christ to fellowship them. Denominations usually wear religious names different from the descriptive terms applied to the Lord's church in the New Testament (e.g., Lutherans, Catholics, Baptists, Pentecostals, Latter Day Saints, Adventists, Jehovah's Witnesses, Methodists, Presbyterians, Christian Church, Disciples of Christ, etc.). Denominations depart from New Testament worship by adding or subtracting according to their preferences (e.g., instrumental music, candles, incense, deviations respecting the Lord's Supper, etc.). Denominations disregard the authority of the Scriptures by altering doctrine (e.g., salvation, leadership and church government, morality, etc.).

Remember, one must turn exclusively to the New Testament to learn what God has authorized. Hence, we conclude that Jesus Christ will not be returning to retrieve churches that he did not establish and over which he is not the Head. Further, Christians cannot fellowship anyone who does not continue in the doctrine of Christ, but rather they are to expose them. The churches of Christ do not fellowship denominations because they are not authorized to fellowship them.

Likewise, concerning salvation, one must turn to the New Testament exclusively to learn what God has authorized. Erring Christians must repent and pray (Acts 8:22; 1 John 1:9), while unbaptized believers need to be baptized to be saved (1 Peter 3:21; Mark 16:16).