The church is the body of Christ. It is so identified numerous times in scripture: (Romans 12:4-5; 1 Corinthians 12:12-13, 27; Ephesians 1:22-23; 4:4; 5:23, 30, 32; Colossians 1:18). Obviously, a church building cannot fit such and identity. The church is that body of obedient believers who have become faithful followers of Christ.
It's not enough to simply believe in Christ. Belief, by itself, does not make a person a member of His body, the church. Jesus gave the standard of living faithfully, obediently by His teachings as distinguishing a true Christian from the world: "If you abide in My word, you are My disciples indeed" (John 8:31). The apostle John emphasized that living faithfully by the teachings ("doctrine") of Christ is absolutely essential. "Whoever transgresses and does not abide in the doctrine of Christ does not have God. He who abides in the doctrine of Christ has both the Father and the Son" (2 John 9). According to Jesus' own words, "If you love Me, keep My commandments" (John 14:15).
A person comes "into Christ" through baptism. The apostle Paul wrote, "Or do you not know that as many of us as were baptized into Christ Jesus were baptized into His death?" (Romans 6:3). He stated this fact again in his letter to the Galatians: "For as many of you as were baptized into Christ gave put on Christ" (Galatians 3:27). Baptism not only serves as the means by which a person comes into Christ, but it is also the point at which he is granted forgiveness (Acts 2:38; 22:16) and salvation (Mark 16:15-16).
When a person comes to salvation in Christ, the Lord Himself adds that person to the church, His body. "And the Lord added to the church daily those who were being saved" (Acts 2:47). Understanding the special, personal relationship the church has with Christ, and the fact that it is made up of the truly saved, should produce remendous respect and appreciation for it...