I am interested in the chronology of the events in Revelation. We know the abomination of desolation occurs at the mid point of the tribulation. When do the two prophets start their ministry?
The two witnesses are first introduced in Rev. 11:3, two chapters before the beginning of the Great Tribulation on Earth. This tells us that their ministry will begin in the lull between the 6th and 7th trumpets and will end prior to the end of the Great Tribulation. This explains why the world will have time to celebrate their deaths at the hand of the anti-Christ. Also notice that in Rev. 11:7 through Rev. 11:14 John skipped ahead to describe the end of their 1260 day ministry. At Rev. 11:15 he went back to where he left off at Rev. 11:6.