When Jesus predicted His death, He also described its result.
I am the good shepherd. The good shepherd lays down his life for the sheep… And I have other sheep that are not of this fold. I must bring them also, and they will listen to my voice. So there will be one flock, one shepherd (John 10:11,16).
For as in one body we have many members, and the members do not all have the same function, so we, though many, are one body in Christ, and individually members one of another (Romans 12:4-5).
And let the peace of Christ rule in your hearts, to which indeed you were called in one body. And be thankful (Colossians 3:15).
“One body” is another way of saying “one church.” (Colossians 1:18 has already set the stage, calling Christ “the head of the body, the church.”) One head has one body. Hence Scripture never supports the idea that believers can make or choose their own denominations. Even from eternity, Christ planned to establish just one united group (Ephesians 2:14-16; 3:10- 11; 4:1-6). That is the gathering of His own group, just as He promised, “I will build My church” (Matthew 16:18).
So we ask again, “What is Christ’s church?” Human answers helped to create the problems. For the better answer, why not try God’s Word? Remember that Paul said,
So we, though many, are one body in Christ, and individually members one of another (Romans 12:5).
Do you see where these members are found? They are “in Christ.” And didn’t Romans show how these believers came to be “in Christ”? All of them “have been baptized into Christ Jesus” (Romans 6:3). Galatians confirms this truth.
You are all sons of God through faith in Christ Jesus, for all of you who were baptized into Christ have clothed yourselves with Christ (Galatians 3:26-27).