I was given a reed like a measuring rod and was told, “Go and measure the temple of God and the altar, with its worshipers. 2 But exclude the outer court; do not measure it, because it has been given to the Gentiles. They will trample on the holy city for 42 months. (Revelation 11:1-2)
Jerusalem is not only the capitol of Israel, but it is the city where God chose in times past to have His Holy Temple built. John here is predicting that during the tribulation period the unbelieving Gentiles (i.e. non-jews) will conquer and desecrate Jerusalem for three and a half years. Of course the city of Jerusalem has been “trampled” by Gentiles many times before. Even in our currently day Jewish control of Jerusalem is limited and disputed. But John is talking about a literal three and a half years in the future that have not yet happened. This will take place when a world leader, known in the Bible as the Antichrist, makes a seven year peace treaty with Israel that will allow temple sacrifices to resume (Daniel 9:27). but this man will break the treaty, desecrate the temple (II Thessalonians 2:4), and try to kill all the Jews in Israel (Matthew 24:18-20). Some of the Israelis will be barely escape to a place of refuge that God has prepared for them in the desert (Revelation 12:14)
The passage we are reading from now (Revelation 11:1-13) describes what will take place back in Jerusalem/Israel as it is occupied by unbelieving Gentiles for the next three and a half years. God will send two powerful “witnesses” to preach to the unbelieving Gentiles. Verse 1 indicates that these witnesses may have power to supernaturally protect the inner court of the temple, and possibly some worshippers of the one true God from continued desecration/destruction at the hands of the antichrist and his forces.