The assembly, the church, is formed by the Holy Spirit baptizing all individual Christians into one body (1 Cor. 12:12-13). The assembly cannot fail because the body of Christ is the workmanship of God in sovereign grace. It is not possible for God’s work to fail – the gates of Hades will not prevail against it (Matt. 16:18). The body of Christ is also known as the bride of the Lamb. During the Christian dispensation, her two main responsibilities are to be the pillar and ground of God’s truth in testimony before the world (1 Tim. 3:15), and to always hold the constant expectation of Christ’s coming for her to take her as one complete body to the Father’s house in heaven (John 14:1-3). In Scripture, this is known as keeping the patience of Christ (Rev. 3:10). The rapture will fulfill the heavenly calling of the church (1 Thess. 4:13-18).
Some articles and chapters which detail what the church is and this event which ends her time on the earth: