The Lord Jesus Christ promised to build His church, "and the gates of Hell shall not prevail against it" (Matthew 16:18). He kept His promise; He built His church. The church belongs to Jesus. He paid for His church with His own blood (Acts 20:28). Fifty days after conquering death by His resurrection, Jesus began adding saved souls to His church (Acts 2:1, 47). He added the souls which gladly received the Gospel, believed it, and obeyed it (Acts 2:41). These obedient believers enjoyed harmony, unity, charity, and joy (Acts 2:42-46). These were the first members of the Lord's church (Acts 2:47).
The church that Jesus built has only one standard by which it exists, and that standard is the doctrine of Jesus Christ (Acts 2:42; Philippians 3:16; I Corinthians 1:10; 4:17). It is not a denomination, nor does it include denominations. There are no creed books; the Bible is the only source of doctrine (Acts 2:42; II Timothy 3:16). There is no need for councils, synods, or authoritative conventions; Jesus rules as the Head of His church through His unchanging Word (Ephesians 1:22-23; Colossians 3:16-17; Hebrews 13:8). Those who readily receive this Word become obedient Christians (Acts 2:41; 13:26), while those that reject or revise Christ's Word have rejected salvation (John 12:48; Galatians 1:6-9).
Anyone who is willing to obey Christ's Gospel can be added to the Lord's church. God "would have all men to be saved and to come to the knowledge of the truth" (I Timothy 2:4). It is the responsibility of the church to take the saving Gospel of Jesus Christ to all the world. Having spent three years teaching and training His apostles, Jesus issued a final instruction just before His ascension: "Go ye, therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the world. Amen" (Matthew 28:19-20). Jesus expects His church to share His saving Gospel with a lost and dying world.