As we come to Revelation 2 and 3 we see letters written to seven churches which are representative churches. These letters present God's truth to us from several different perspectives.
Apostasy is turning away from truth, an abandoning of what one once professed to believe. This is the greatest challenge that faces each and every church.
The decline of faith can be traced from the seven churches, right on down to the great apostate church of Revelation 17.
Apostates are those who were once inside the church, they had professed faith in Christ, were baptized and joined the church, but had never truly been born again (Matthew 7:21-23),
Sometimes they leave the church and sometimes they remain in the church. Down over the centuries the church has gradually been infiltrated with unsaved people, and as time goes on, the number of apostates continue to grow, until, many professing churches have no truly saved people in them. So, an appropriate title of chapters two and three might be, "The Great Apostasy of the Last Days traced from the beginning of the Churches' history."
The Letter to Ephesus reveals a picture of the powerful, dynamic, apostolic church of the first century.
The Letter to Smyrna describes the second and third centuries with the martyrdom and persecution of the church of that period.
The Letter to Pergamos reveals the compromise and corruption of Christian testimony by the union of church and state under Constantine.
The Letter to Thyatira reveals the period of the Dark Ages from the sixth to the fifteenth centuries under Catholicism.
The Letter to Sardis tells about the rise of Protestantism, and its ultimate corruption.
The Letter to Philadelphia and the Letter to Laodicea are for the last two churches. Many believe that these two churches are found running side by side in the world, in the years immediately preceding the Rapture. Philadelphia came first and was the church that was pleasing to the Lord, a church which received no condemnation, but only commendation. Philadelphia was promised that it would not go into the tribulation period (Rev. 3:10). Laodicea seems to have come out of Philadelphia, and through its lukewarmness and compromise, will ultimately be lost in the apostate harlot church in the tribulation period.
When we look at Christendom today, we see that the great apostasy is upon us, with Christ and His Word dishonored by those who profess to be a part of the Church of Jesus Christ.