"And he is the head of the body, the church; he is the beginning and the firstborn from among the dead . . . the mystery that has been kept hidden for ages and generations, but is now disclosed to the saints . . . Christ in you, the hope of glory" (Colossians 1:18, 26-28).
Discussing the origin of Christianity requires the review of an intricate story spanning time and eternity. Instead of a simple beginning, we consider Christianity’s origin from several points of view. Acts 2 records the birth of the church at Pentecost. This was indeed a Feast of Harvest (Exodus 23:16), because a harvest of about 3,000 souls took place on that day when the Holy Spirit came upon the apostles and disciples (Acts 2:1-41). Biblically, Christianity is not a building or religion but the church, or household of God. It is embodied in Christ and His people, individually and collectively. Before time began, the church was conceived in the mind of God. Then, “when the time had fully come" (Galatians 4:4), God sent His only son, "born of a woman, born under law" to be the church’s true founder, foundation, and head (1 Corinthians 3:11). As the first of the chosen ones (1 Peter 2:6), Jesus, the anointed one, died as the perfect Passover lamb fifty days before the events of Acts 2. Before that, He prepared the apostles for three years, giving them the Father’s Word and keeping them in His name (John 17:12, 14). After His resurrection He breathed into the apostles the breath of eternal life in the form of the Holy Spirit, who was to indwell them (John 20:22; cf. John 14:25-26). They became the seeds of the new church, which sprouted into thousands when the Holy Spirit came upon them, empowering them to witness, preach, and carry out the mission Jesus gave them. Rising from the dead, Jesus was the first fruits of God’s Kingdom; ''then, when he comes, those who belong to him will also rise, never to die again (John 11:25-26). Thus, Jesus is the one foundation and source of the church.
The Old Testament had prophesied that a “shoot” would come from the “stump” of Jesse (King David’s father) and that this “branch” would bear fruit (Isaiah 11:1, 10). Jesus is that Messiah or Christ. He is the hope of Jews and Gentiles. "The Root of Jesse will spring up, one who will arise to rule over the nations; the Gentiles will hope in him" (Romans 15:12; cf. Revelation 5:5; 22: 16). Peter learned that Jesus is not merely a human being, the Son of David, when God showed him that Jesus is "the Son of the living God." To this, Jesus added that He Himself is the Rock or foundation upon which He would build His church (Matthew 16:16-18; see also Isaiah 26:4). The building of the church upon Jesus, the Rock of Israel (Isaiah 30:29), is taught in 2 Corinthians 6:16 (see also Ephesians 2:21-22).
Some writers mention that the word for “church” in the original Greek is ecclesia, meaning “a called-out assembly” (εκκλησιαν – Matthew 16:18) and that the church is formed by the “elect” or chosen (Mark 13:20; Luke 18:7; Romans 8:33). Yes, the elect have been called out from the kingdom of darkness, but we have also been called into God’s family as adopted children. “The Spirit himself testifies with our spirit that we are God’s children” (Romans 8:16; cf. Ephesians 5:1, 8). We are chosen, but Jesus is the first of the chosen (1 Peter 2:6), and He lives in us as we live or abide in Him (John 8:31; 15:4-9).
Christians are individually in Christ even as the church as a whole is in Christ (Romans 12:5; 1 Corinthians 1:2, 30). The mystery of Christ and the church is brought out in Paul’s discussion of the mystery by which two become “one flesh” in marriage, in Ephesians 5. There the apostle writes that “this mystery is profound,” referring to Christ and the Church (Ephesians 5:32). The tense of the Greek word translated “mystery” (μυστηριον) is singular. This grammatical detail shows that in their unity Christ and the church are one mystery. They are not a mixture or compound; rather, their union is like that of a man and woman in holy matrimony who become “one flesh” or a new family unit without giving up their individuality (Genesis 2:24). In marriage a couple becomes legal “kin,” even though they are not blood relatives as Adam and Eve were. Similarly, through Christ God legally adopts the chosen as children (Ephesians 1:5). Because of this, and because Christ lives in each member of the church, His spiritual body, He is our hope of glory (Colossians 1:18, 26-28). Christ’s presence in Christians answers Jesus’ prayer in John 17: “My prayer is not for them alone. I pray also for those who will believe in me through their message, that all of them may be one, Father, just as you are in me and I am in you” (John 17:20-21; see also John 17:11).
The connection between the words “church” and “Christianity” is old and complicated, but we can simply say that Christians do not go to church; rather, they are the church. Most disciples who first joined the growing church were Jews. Like Paul (Philippians 3:5; Romans 11:1), they considered themselves Israelites, descendants of Abraham, to whom belonged the covenants, the giving of the law, etc. (Romans 9:4-5). They acknowledged the Lord Jesus as Messiah and God but did not (at first) call themselves “Christians.” At Antioch in the first century, outsiders first called the followers of the Christ “Christians” (Acts 11:26). They thought “Christ” was the proper name of the God whom they worshiped, not aware that “Christ” means “anointed” and that Jesus is the Christ. As for “church,” some early Christian writers used this word to refer to the place where people worshiped (i.e., the church building). But in the New Testament, the word translated “church” refers to the “household of God.” In Ephesians 2:19, the Greek word translated “household” is οἰκεῖοι. This plural form refers to all those who belong to the immediate family of God, i.e., those who are spiritually family in the faith (Galatians 6:10; Ephesians 2:19). As members of this universal household, Christians have taken root and blossomed among the various peoples and in almost every language group in the world.
Now, let’s look beyond history to reflect on the eternal origins of the church (i.e., “Christianity”) in the mind of God. Even as God chose Israel (Deuteronomy 7:6; 26:18), He also elected the church in Christ “before the foundation of the world” (Ephesians 1:4). In eternity past, God willed that the elect would be saved and made part of His household by adoption. “He predestined us for adoption as sons through Jesus Christ, according to the purpose of his will” (Ephesians 1:5). However, the church born on Pentecost has not yet realized its ultimate purpose in its development. The church is not yet the spotless bride of Christ (Revelation 19:6-8), in accord with God’s purpose for it, as we read in Ephesians 1:4: “For he chose us in him before the creation of the world to be holy and blameless in his sight.” The fulfillment of this prophetic purpose which God set forth in Christ (Romans 8:28; 9:11) “to be put into effect when the times will have reached their fulfillment” (Ephesians 1:10) does not depend on “… anything we have done but because of his own purpose and grace. This grace was given us in Christ Jesus before the beginning of time” (2 Timothy 1:9).
One reason the “visible” church is not perfect is because within its ranks there are false Christians. Jesus told the apostles that within the church there would be a mixture of “wheat and chaff,” genuine saints and secret, unrepentant, self-deceived sinners (hypocrites). Considering that Christ has not yet returned in power and glory (Matthew 26:64; Mark 13:26), and that the elect have not yet been revealed as God’s children (Romans 8:19; 1 John 3:2), the mystery of Christ and the church, kept secret for long ages (Romans 16:25), remains partially concealed. The unveiling of the church will not take place until the moment we are changed, as 1 Corinthians 15:51-53 says. The real hope for Christians is not that we will be immortal (the damned in hell will also be immortal, but they will be without Christ), but that Christ lives in us now (Colossians 1:28).
This brings us to a final thought about the church’s present hidden-ness and ultimate unveiling. We have been redeemed, we are no longer slaves to sin, and death no longer has dominion over us (Romans 6:5-9). Nevertheless, our “body of sin” or “body of death” (Romans 6:6; 7:24) has yet to be “brought to nothing.” We still await the resurrection and redemption of our sin-stained flesh. This will take place when the Lord returns for us. Then “we shall be like him; for we shall see him even as he is” (1 John 3:2). Then, our glorious, imperishable spiritual bodies will be revealed (Philippians 3:20-21), and we will no longer be burdened by what remains of the carnal or sinful mind. Thus, in a real sense, the church or Christianity in its perfection, as the undefiled and glorified bride of Christ, continues to wear a discrete veil, until she is called to heaven in glory at the marriage supper of the Lamb. This event is prophesied in Revelation 19:6-8, where we read, “Then I heard what sounded like a great multitude, like the roar of rushing waters and like loud peals of thunder, shouting: ‘Hallelujah! For our Lord God Almighty reigns. Let us rejoice and be glad and give him glory! For the wedding of the Lamb has come, and his bride has made herself ready. Fine linen, bright and clean, was given her to wear.’ (Fine linen stands for the righteous acts of the saints.)”