Then I was given a measuring rod like a staff, and I was told, “Rise and measure the temple of God and the altar and those who worship there, but do not measure the court outside the temple; leave that out, for it is given over to the nations, and they will trample the holy city for forty-two months. And I will grant authority to my two witnesses, and they will prophesy for 1,260 days, clothed in sackcloth.” (Revelation 11:1-3, ESV)
There are various ways this passage is interpreted. By far the most popular is that this vision depicts activity just a few years prior to Jesus' second coming, during a great seven year tribulation period. The references to time, 42 months and 1,260 days are viewed as actual periods of time for this activity.
A less popular view, but gaining some popularity, is that vision is about the fall of Jerusalem and the destruction of the Temple around 70 AD.
Personally, I think the truth literally is between these two views.
This vision in this section of Revelation is between the sixth and the seventh trumpets. The language of Revelation is highly symbolic. Some prefer to follow a motto that we are to read and interpret Revelation literally as much as possible unless the literal meaning is impossible. I think a better approach is to recognize the symbolic form of the visions and see how those symbols work. This is recognizing that Revelation fits a genre of apocalyptic literature, and that the Holy Spirit is painting with metaphors. Numbers are included in those metaphors. The number three in Revelation, particularly with reference to God where there is a triad statement (e.g., the one who was, who is, and is to come) refers to the Trinity. The number four often refers to earth or the creation (e.g., the four living creatures, the four winds). We now see the numbers 1,260 days, 42 months, and later, time, times, and half a time -- which refer to the same period of time, 3 1/2 years. In the ancient Jewish calendar, a year was 360 days, or 12 thirty day months. Do the math and you see that all these refer to the same period of time. This period of time is associated with difficulty, tribulation, and persecution. A natural question is when does this time begin? Revelation chapter 12 indicates it begins with Christ's ascension, which I'll examine in two days on December 15. This period of 42 months or 1,260 days is a metaphor for the period from Christ's first advent, particularly his ascension, until his second coming, or soon before Christ's second coming.
Revelation chapter 11 presents two images. The first image is measuring the temple, specifically the alter and those who worship there versus the outer court. The second image is the two witnesses.
The metaphor of measuring indicates ownership. Those withing the boundaries of the measurement, the ones who worship God, belong to God and in a fundamental sense they are protected by God. However, the outer courts of the temple are not measured. The outer courts will be trampled upon for 42 months. Those who are associated with the temple will face trials and persecution. However, all who truly worship God, who are the sealed ones, are ultimately protected by God.
The two witnesses are called "the two olive trees and the two lampstands that stand before the Lord of the earth." To understand these metaphors, we need to be reminded what the number two was used for in the Bible. In legal trials, there was the requirement that charges would be corroborated by two or three witnesses. The number two is not a literal number per se, but symbolic metaphor that emphasizes the "witness" purpose of the two witnesses. Further, the witnesses are are referred to as lampstands. Lampstands in chapter 1 stood for the churches. Thus the two witnesses represent the church from Christ's ascension until his second coming. The function of the church shown in this vision is a legal testimony, where the church presents the charges of idolatry and sin to the dwellers on the earth who don't know God. The church has considerable power. It has the power, through prayer, to bring God's judgment upon the earth in various ways. At the close of the 1,260 days, there will be a brief time (three and a half days) where the church will suffer intense persecution, to the point of looking dead, prior to Christ's second coming. People will rejoice over the apparent death of the church. But God will vindicate his church, to the terror and amazement of the dwellers on the earth. This will happen at the judgment, where the earth is destroyed and transformed.
Revelation does not paint a picture where Christians escape from trouble and persecution. Personally, I would prefer a rapture of the church before the tribulation, as the Left Behind series does. It fits my desires to escape pain, difficulty, and suffering. I always prefer the easy way out. But God does not give that option to Christians. But what God does give is ultimate victory, conquering. Conquering the same way that Christ conquered, through death. We are Christians -- little Christs. If Christ was persecuted and suffered, what right do we expect to escape persecution and suffering in our lives? But God grants us strength to endure and to achieve victory.
This is not a popular message with the wider Christian culture today. We have a crisis of a crossless Christ. People are told to try Christ to solve their problems, to have a happy life, to fix their lives, to even get material wealth. They way of the cross, the way of endurance, perseverance, is not taught in many circles. Even our popular eschatologies have escapism, a "beam me up, Scotty" mentality when the problems of the end of the age come. Further, such an attitude is a mockery to the millions of Christians who have and are enduring unimaginable suffering for Christ throughout the centuries. The intensity of the great tribulation was and is very real to them.
We are to fix our eyes upon Christ, not escaping, not material comforts, not safety. Christ's power will enable us to serve and endure to victory.
Once again I quote Paul:
For I consider that the sufferings of this present time are not worth comparing with the glory that is to be revealed to us. ...