John the Apostle, the brother of James, ministered in Ephesus during his later years and was exiled to the isle of Patmos, not far from Ephesus. Of the seven letters of Revelation 2&3, Jesus wrote to Ephesus first, mediated through John. Rev. 2.1-7 is the only letter to the Ephesians.
It is fairly clear that the Apostle John was the younger brother of James and probably only about 12-14 years of age at the start of Jesus’ ministry. This is why Jesus spent valuable time instructing him, since John would have not needed to relearn unwarranted beliefs, like the other disciples. John, being a young teenager in 30 CE could have easily lived to 90-95 CE when his gospel and Revelation were written. After reading the many different theories of authorship of Revelation, I firmly believe it was John the Disciple and brother of James, sons of Zebedee.
The bible records two letters to Laodicea. Jesus wrote one in Rev. 3.14-22 rebuking this materially wealthy city. The other biblical letter to them was earlier from Paul. To find it requires detective work.
Skeptics have long discounted Ephesians as one of Paul’s letters since it is inconsistent with both his common practice and historical records (Acts). There is not one personal greeting in all of the letter whereas, in Paul’s other letters, personal greetings are a prominent feature. In Eph. 1.5, Paul says he “heard about their faith.” This is at odds with what Paul said to the Ephesian elders in Acts 20.31: Therefore be alert, remembering that for three years I did not cease night or day to admonish every one with tears (ESV). If “Ephesians” was really written to another church, many of the sceptic’s qualms would be resolved.
Paul’s epistle, which we call “Ephesus,” really has to be “to Laodicea.” Through the centuries of church history, many writers, good and bad, have recognized this fact. The “to Ephesus” is probably a later addition from a scribe who found a copy in Ephesus. Paul (and the Spirit) wanted the Christians to compare different perspectives, both true, in the letters of Colossians and Laodicea. This is the only way for Col. 4.16 to be fulfilled: And when this letter has been read among you, have it also read in the church of the Laodiceans; and see that you also read the letter from Laodicea (ESV). Paul instructed both of these letters to become circular, and therefore copies were commissioned to accomplish this command. Since the Laodicean Letter became circular, this fact makes it highly unlikely that it would be lost to history. So, where is the Epistle to Laodicea?
The city of Ephesus, scarcely 100 miles to the west by way of a prominent trade route, would have been a natural repository for one of these copies. The copy at Ephesus would have served subsequent generations who didn’t know Paul, personally, like those among whom he ministered. Because Paul spent nearly three years in Ephesus that church didn’t need a correspondence the way that Laodicea and Colossians did. Paul only “heard about their faith” (Col. 1.4, Eph. 1.15). All of Paul’s letters were already becoming circular as seen from 2Pet. 3a: as he does in all his letters when he speaks in them of these matters (ESV). Since Paul commands this letter (“Ephesians” via Col. 4.16) to become circular, this may have been a reason for it to lose its address.
Whether my contention is believed or not, it is still beneficial to carefully compare the letters of Colossians and “Ephesians” since they both given similar instruction slightly differently. In several places, I believe, they explain each other.