According to Rev. 11:3-6 the two witnesses prophesy & have power for 1,260 days.  Rev.11:3, "And I will give power unto my two witnesses, and they shall prophesy a thousand two hundred and threescore days, clothed in sackcloth."  

What do they prophesy about? Do they prophesy about the soon second coming of the Messiah Jesus Christ to judge the people on the Earth and about salvation through His name under the New Testament blood covenant? Do they prophesy about the coming Beast, and not to worship him or his image nor to take his mark in the right hand or forehead? 

Do the Two Witnesses help the Jewish people build the third temple in which animal sacrifices will resume for their sins when animal sacrifice for sins was done away when the Lord Jesus Christ became the sacrifice for sin about 2,000 years ago?  If the two witnesses are the prophet Elijah whom the Jewish people expect, and the prophet Enoch or Moses, they would both have known some time after they were taken to heaven alive that Jesus Christ was the Messiah and the Savior of the world who would die on the cross and shed His blood at some future point in time and rise from the dead so they would have known about the everlasting New Testament blood covenant.  Therefore, in my opinion I can't see the Two Witnesses helping the Jewish people to build the third temple to resume animal sacrifices for their sins.  If anything, I can see the possibility of them preaching repentance, the gospel and about the New Testament blood covenant in Jesus' name so that people will be saved during the tribulation period.