Must each Christian be a member of a local congregation? Lake so many questions, this one cannot be properly answered either yes or no without considering existing circumstances. The reason for this is that the essentiality of local church membership is contingent upon two important factors: (1) Being where other Christians are and (2) Their walking according to truth in their congregational practices. I would certainly deny that one is obligated to be a member of a local church when such is impossible due to there being no others with whom he could unite or when those who compose the church are engaged in unauthorized congregational activities. But granting these two conditions, membership is essential!
The local church of Crist is a relationship (fellowship) between individuals. This fellowship is designed for those who are partakers of the common salvation, dedicated to the common service of God, subjects of the common authority of Jesus Christ, and renderers of common worship. In view of man’s gregarious nature it seems only natural that God would make provision for Christians to enjoy fellowship (mutual, active participation in common interest) in the fulfillment of their work and worship. The Lord has made such provision in His Word. The local church is the result of that provision. If God gave the local church, membership is necessary. There can be no church without members thereof. There can be no members thereof without membership therein.
Those who are to oversee the churches of Christ (elders, pastors, or bishops) are often mentioned in the New Testament (cp. Acts 11:30; 14:23; 15:23; 20:17). Their duties are discussed (Acts 20:28-31; 1 Peter 5:1-9). These scriptures set forth the fact that elders function in the local church. For them to guide and oversee there must be someone or something or both for them to oversee. This oversight, then demands a local church, which demands members, which demands membership.
Christians are to be, not only a part of, but, to some extent amenable to a local church. This is seen in the responsibility of local church discipline. The Lord expects of us purity of life and teaching (Gal. 1:6-9; 5:19-23). He also demands that the congregation exercise corrective discipline in cases of impurity (2 Thes. 3:6; Romans 16:17, 18; 1 Cor.5).
Local church discipline demands a local church and a local church demands membership. The example of the early disciples indicated that Christians are to be members of local congregations. When Paul went to Jerusalem, he “assayed to join himself to the disciples” and eventually “was with them (Acts 9:26-28).” In Antioch he and Barnabas “assembled themselves with” the church over a period of one year (Acts 11:25,26). They were “in the church that was at Antioch (Acts 13:1).” In fact, when Paul and others found no local church in existence upon the conversion of souls, they established one (Acts 18:27; Rom.16:1f). Are you a faithful, active member?