Jesus said, I will build my church (Matt 16:18).
We see the fulfillment of that promise in the first two chapters of the New Testament book of Acts. The church had a great beginning as the apostle Peter preached the first gospel sermon and in one day about 3,000 souls "gladly received his word" and were baptized (Acts 2:41). Then we learn that "the Lord added to the church daily those who were being saved" (Acts 2:47).
Jesus declared, "All authority has been given unto me in heaven and on earth" (Matthew 28:18). Shortly thereafter, Jesus ascended up into heaven, but He told his apostles that He would send the Holy Spirit to remind them of all that He had taught them (John 14:26), and to guide them "into all truth" (John 16:13). These apostles recognized Jesus as the "head over all things to the church" (Ephesians 1:22). Any church that claims to belong to Christ should be the same as the one He built and that you can read about in the Bible. Anything else is something other than the Lord's church.
Who belongs to His Church?
From its very beginning we learn that "the Lord added to the church daily those who were being saved" (Acts 2:42). One might wonder how one becomes a saved person who is added to Christ's church. Actually, the Bible tells us, clearly and plainly, what one must do to be saved. To put it simply, one must believe and obey the gospel (Romans 1:16).
We find that "without faith it is impossible to please God" (Hebrews 11:6). Also, Jesus warned that "if you do not believe that I am He, you will die in your sins" (John 8:24). So, we find that in order to be saved you must believe in Jesus as the Son of God. While many think that this is all you must do to be saved, the Bible indicates that you are not justified by "faith only" (James 2:24). Faith must prompt you to repent of your sins. Jesus warned that, "unless you repent, you will all likewise perish" (Luke 13:3). He also requires that you confess your faith in Him (Matthew 10:32-33). Finally, just like those in the first century, you must be baptized "for the remission of sins" (Acts 2:38). It is at the point of baptism that you "wash away your sins, calling on the name of the Lord" (Acts 22:16). The apostle Paul confirms this by declaring, "For as many of you who were baptized into Christ have put on Christ" (Galatians 3:27).
The Church is the People NOT the Building
Paul taught, "God...dwelleth NOT in temples made with hands" (Acts 17:24) and that the church is made up of "lively" stones -- that is, people (1 Peter 2:5)
The Church is NOT a Denomination
The Lord's church is not Catholic, Jewish or Protestant -- it is undenominational. Denominations are "churches" established by men, but the Lord's church is of divine origin (see Matt 16:18).
The Church is NOT a Political Organization
The Lord's church has no political agenda. Jesus said, "My kingdom is not of this world" (John 18:36).
The Church is NOT a Social Institution
When Paul wrote to the Roman Christians he said, "For the kingdom is not meat and drink, but righteousness and peace, and joy in the Holy Spirit" (Rom 14:17).