A church is an assembly of believers in Jesus Christ who come together to worship God and have fellowship with each other, through prayer and through the reading of God's Word, the Bible. It is also used to refer to the building that is designated as the place for a church to assemble in. The whole body of true believers in Christ, regardless of their denominational affiliation, are collectively known as the Church, although certain denominations such as the Roman Catholic Church in addition to cults that label themselves as Christians tend to refer to themselves as "the one true Church", as if salvation in Christ cannot be found anywhere else except within their organization.
Jesus in Scripture promised that "on this rock I will build My church, and the gates of Hades shall not prevail against it". (Matthew 16:18) However, over the years, the Church has suffered not only persecution but also division over doctrines and increasing moral compromise from within the body of believers. Despite this, the Lord is fully aware of who are truly His followers and has promised to deliver them from "the hour of trial" that will come upon the earth to test those who dwell upon it. This took place in "The Rapture" and "Left Behind" when Jesus took the true believers, plus newborn babies, the unborn, and children who were too young to be held accountable for their actions, to heaven with Him. As Bible students consider the Church to be "the bride of Christ", the Left Behind books also show in some detail the marriage that took place between Jesus Christ and His bride in heaven.
During the Tribulation, underground churches had to be formed as true believers would be persecuted and those that called themselves "churches" but had no true believers in Christ would become part of Enigma Babylon One World Faith, until Carpathianism became the only legal state religion, in the Left Behind books. At the end of the Tribulation, Jesus returned with His army of saints -- the church that He took with Him to heaven -- to defeat the Antichrist and his armies and to set up His Millennial Kingdom.
In striking contrast to the Church being pictured as a chaste virgin that is "betrothed" to Christ, Enigma Babylon can be seen as part of the fulfillment of the Great Harlot mentioned in Revelation chapters 17 and 18.