How long will the Great Tribulation mentioned in Bible prophecy last?
The "great tribulation" refers to the time of crisis at the close of the age of man. Jesus spoke of "great tribulation" in Matthew 24:21 and told the apostle John to write of it in Revelation 7:14.
Several events are prophesied to occur during the crucial last days:
The area outside of the temple in Jerusalem will be controlled by non-Israelite powers (Revelation 11:2).
The two witnesses of God will fulfill their commission (verse 3).
The Beast power, a counterfeit of the Kingdom of God, will dominate world politics, religion and economics (Revelation 13:5).
An unparalleled "time of great trouble" will come on the people of Israel, affecting also "the holy people" (Daniel 12:1, 7).
Notice that a common time period is mentioned in connection with these events:
42 months (Revelation 11:2; 13:5).
1,260 days (Revelation 11:3).
"A time, times, and half a time" (Daniel 12:7).
These are variations of the same period—3 1/2 years (not seven years, as commonly suggested by many today).
Note Wycliffe Commentary's notes on Daniel 12:7:
"The consummation is to take place when the three and one-half times (3 1/2 years; 1,260 days; 42 months) so frequently mentioned in Daniel's previous prophecies and in the Revelation are run out."
The idea of a seven-year tribulation is based on a single reference, Daniel 9:27, which tells of a covenant made "for one week" by one who will cut off sacrifices "in the middle of the week," an act that will herald the beginning of the crisis at the end. Each day in prophecy, goes the reasoning, represents a year and hence a week refers to a seven-year period.
We believe the weight of evidence supports that this verse refers to Christ. The Messiah was cut off in the midst of a week, or after 3 1/2 years of His earthly ministry, as well as on a Wednesday, the middle of a literal week.
Others believe this verse refers to the Antichrist. Even if this were a prophecy of the Antichrist, the crisis begins "in the middle," or after 3 1/2 years, leaving another 3 1/2 years remaining for the fulfillment of the close-of-the-age events mentioned above. So the period would be the same as prophesied in the above references to the main events of the end time.
Clearly the Bible does not support the idea of a seven-year Great Tribulation.