A Preview of Great Tribulation
 

The Lord must remove all of the seals of the scroll before this script of the judgments of His coming hour of trial opens

Each of the 6 seals is a symbolic portent of the prevalent conditions that will exist during the tribulation period .... not the literal action events that will play out upon the earth which will not begin until all 7 seals are removed, the 144000 mortals of the children of Israel are sealed for protection, and a short silence in heaven [Revelation 7:1-8; 14:1-7; 8:1-6]

The 7 portents:
The continuance of the spreading of the gospel
Intense angelic and human warfare
Worldwide economic collapse
Massive human death
Martyrdom of those who become believers
Upheaval on the earth caused by judgment and human reaction
The short silence in heaven just before the judgments begin

These portents are previews and not part of the literal time lapse of the tribulation period

Understanding this will aid the student of Revelation with the correct rendering of the prophecy's unfolding

One also needs to understand that the portent of the 6th seal is about the beginning of the tribulation period and not the ending of it [Revelation 6:12-17]

Jesus said that the entire period of judgment [2550 days] at the time of the end of this present age will be unprecedented great tribulation during which the gospel of His soon coming kingdom on the earth will be preached [Matthew 24:21; 24:14; Revelation 14:6-7]

He will then appear visibly to the survivors of the tribulation period at the ending [Matthew 24:29-31; 25:31-46; Revelation 1:7]

One should not confuse the portent of the 6th seal with Matthew 24:29-21 as do the proponents of the post-tribulation view

There are distinct differences between these two passages of scripture, the first noting the beginning of the 2550 day tribulation, and the second describing the ending of the same period

Re: A Preview of Great Tribulation
 

Jesus spoke of the sixth seal where people cry for rocks and mountains to cover them when he spoke to the women weeping at Jerusalem. They and their children would do the crying for the covering of rocks and mountains. Let's interpret Revelation by Jesus' words.