Can a Christian become a member of a denomination?
No one is a Christian (child of God) who has not been baptized in the name of (by the authority of) Christ unto the remission of sins (Acts 2:38; Mk. 16:16; Acts 22:16; 1 Cor. 12:13; Rom. 6:3-5; Gal. 3:26-27).
The Lord has only one church. The church is his body (Eph. 1:22-23). The body is the church (Col. 1:18) and there is one and only one body (Eph. 4:4-6). Thus, if the church is the body and the body is the church and there is only one body, then there is only one church. That is, there is only one church with God’s approval meaning, there is only one church which is authorized by Christ meaning, there is only one church which has been purchased by the blood of Christ (Acts 20:28; Eph. 2:13-16; Col. 1:18).
So, can a child of God, a Christian and member of the Lord’s true church, become a member of a denomination and be faithful while doing so? The Bible answer is No, he or she cannot and there are reasons why he cannot be faithful in a denomination.
First, he cannot be faithful to Christ in such a case because he ceases to work and worship with God’s faithful people. He ceases to be in a situation where the truth is being preached and religious error is refuted. He ceases to worship according to New Testament teaching by the authority of Christ. These facts alone is sufficient to make clear that he is not and cannot be faithful when he leaves God’s people and enters a denomination. He cannot be faithful because in entering a denomination, by his action he says that in his view, the Lord church is only a denomination among many other equally valuable denominations which he sees is all equally pleasing to God. Thus, he declares and believes that the church for which Jesus died is neither unique nor essential.
Second, in entering a denomination and working and worshiping therein, he cannot be faithful to Christ because in doing so he attributes the authority of Christ to what is nothing more than human doctrine. He therefore, lives according to human doctrine, supporting the proclamation and spread of human doctrine by giving of his money into the treasury of that denomination and when he tries to teach others, he himself teaches mere human doctrine. Therefore, since it is not authorized by God, no one can be faithful who either teaches or lives by it. As John would say, “Whosoever transgresseth, and abideth not in the doctrine of Christ, hath not God. He that abideth in the doctrine of Christ, he hath both the Father and the Son. If there come any unto you, and bring not this doctrine, receive him not into your house, neither bid him God speed: For he that biddeth him God speed is partaker of his evil deeds.” (2 Jn. 9-11)
Therefore, a person who is baptized into Christ (Gal. 3:26-27) and has become a child of God (Mk. 16:16), and then later enter a denomination from human origins, does remain a child of God, but has become unfaithful. It is certainly the case today that there are Christians who are members of denominations, but they are apostates or deserters of the Faith. They chose to obey false doctrine rather than the truth and the Bible teaches that they cannot reap an eternal life of rejoicing when this life is over if they do not repent and come out of the human religions (Rev. 2:10).
So, just being religious is not enough. Just being sincere and zealous is not enough. Just believing on Jesus is not enough. One must not only be a penitent believer in Christ, but he must also do the will of God (Matt. 7:21). He must be baptized into Christ in order to become a child of God (Gal. 3:27). He must live as a faithful member of the Lord’s church which is the only one with God’s approval. Thus, the Bible does not teach that all others are acceptable too. This is far from the truth. The truth is that Jesus offers to save all men (Tit. 2:11), but he can only save those who obey him (Heb. 5:8-9). And, Christ will not tolerate another gospel (Gal. 1:6-9). Therefore, may we all believe and continue to believe in and obey Jesus Christ, the Son of God.