Thanks Rose and Joe for your replies,
Of course some parts which you all said make sense to me. But my point is if I am staying in Washington and something disastrous happened in New York, of course I would feel for my fellow men but it would not be of immediate concern to me because it happened in New York and not in Washington. There is no urgency for the news of the disaster in New York. Goes the same for the 7 churches in Asia Minor and other churches in the Roman Empire, they would not be urgently concern about what was going to happen in Jerusalem in AD 70. So why the urgency for the warning?
The message of the 7 churches is for all churches in the Roman empire and to all generations of churches thereafter to wake up or disasters as described to the 7 churches in Asia Minor will befall them.
I saw in the web another explanation for the 7 churches in Asia Minor. What it said is that the warnings given to the 7 churches in Asia Minor are the warnings of what would befall them if they did not behave to God's expectations. And these warnings to the 7 churches happened as evident in historical records by the various authors:
Church Period in Church History Dates
Ephesus Apostolic Age Before AD 100
Smyrna Age of Persecution 100 to 313 AD
Pergamos Imperial Church Age 313 to 590
Thyatira Age of Papacy 590 to 1517
Sardis Reformation Age 1517 to 1730
Philadelphia Missionary Age 1730 to 1900
Laodicea Age of Apostasy 1900 to ?
Joseph Seiss, The Apocalypse (1900)
Ephesian: Warmth and love and labor for Christ; defection beginning with a gradual cooling of love, false professions and clergy/laity distinctions.
Smyrna: Sweet and precious martyrdom, but a progression of clergy/laity distinctions and Judaizing tendencies, with an increasing departure from the simplicity of the gospel.
Pergamite: True faith more and more disappearing; clericalism systematized, union with the world.
Thyatiran: Purple and glory for the corrupt priesthood; false prophets enthroned in a time when truth was exchanged for darkness (up to the Reformation).
Sardian: Separation and return to the rule of Christ; many great names, but also deadness, and lethargy (Protestant centuries).
Philadelphian: Closer adherence to Jesus' word, more fraternity among Christians (modern evangelical movement of the 19th century).
Seiss does not give much of a description of the Laodicean church along this same pattern, because he felt that in his day (1900), it was yet to really emerge upon the scene
Clarence Larkin, The Greatest Book on Dispensational Truth In the World (1918)
Ephesian: 70 to 170 AD; "the backslidden church"
Smyrna: 170 to 312; "the persecuted church"
Pergamite: 312 to 606; "the licentious church"
Thyatiran: 606 to 1520; "a lax church"
Sardian: 1520 to 1750; "a dead church"
Philadelphian: 1750 to 1900; "a favored church"
Laodicean: 1900 to the end; "a lukewarm church"
Taylor Bunch, The Seven Epistles of Christ (1947)
Ephesian: The "universal church of the days of the apostles, or the first century of Christianity"
Smyrna: Second and third centuries, "the age of martyrdom, when pagan Roman emperors attempted to destroy Christianity with the violence of the sword"
Pergamite: Covering 250 years (Constantine to Justinian the Great) "the church was exalted to royal power and kingly authority through a union, or marriage, with the state."
Thyatiran: 538 to 1520; the corrupt, political church of the Middle Ages.
Sardian: 1520 to the mid 1700's ("but doubtless embraces the entire history of Protestantism to the end of the gospel dispensation"); the church of the Reformation, and a partial work.
Philadelphian: From the mid 1700's to the present; the church of 18th and 19th century revivals, worldwide missions movements, and renewed expectation of Jesus' return.
Laodicean: Middle 1800's to the end of the Christian dispensation; "a sad comment on modern Christendom."
Chuck Smith, What the World is Coming To (1977)
Ephesian: The early church, up until the death of John.
Smyrna: 2nd to 4th centuries; Roman persecutions.
Pergamite: Beginning in 316; "development of church-state system under Constantine."
Thyatiran: The unrepentant, unfaithful church destined to go through the Great Tribulation.
Sardian: Dead Protestantism.
Philadelphian: The faithful church of the last days.
Laodicean: The apostate church of the last days.
Many Blessings to you.