"And when they shall have finished their testimony, the beast that ascendeth out of the bottomless pit shall make war against them, and shall overcome them, and kill them. And their dead bodies shall lie in the street of the great city, which spiritually is called Sodom and Egypt, where also our Lord was crucified. And they of the people and kindreds and tongues and nations shall see their dead bodies three days and an half, and shall not suffer their dead bodies to be put in graves. And they that dwell upon the earth shall rejoice over them, and make merry, and shall send gifts one to another; because these two prophets tormented them that dwelt on the earth."
"And after three days and an half the Spirit of life from God entered into them, and they stood upon their feet; and great fear fell upon them which saw them. And they heard a great voice from heaven saying unto them, Come up hither. And they ascended up to heaven in a cloud; and their enemies beheld them." (Revelation 11:3-12 King James Version) (see The Two Witnesses)
Who Will They Be?
There has been much misinformed speculation about who God's two witnesses will be. Some think that they will be two angels, such as Michael and Gabriel, but angels are spirit beings who cannot be killed. The two witnesses will eventually be killed. Others guess that they will be two prophets (see Prophecy) from Bible History, such as Elijah and Elisha, or maybe John The Baptist, who will be resurrected at that time. But, the Bible says that when the righteous are resurrected, at Christ's return, not before, it will be as immortal spirit beings, who also cannot be killed. Angels or resurrected prophets do not fit the reality God's Word. Two modern-day human beings do.
God chooses those who serve Him, and for that reason His two witnesses will not be volunteers. It is also quite possible that they will have no idea that they have been chosen until very near the time that their ministry is about to begin. This was very often the case with the prophets throughout the Old Testament, as well as with the apostles in the New Testament. God's servants were given to know what they needed to know, when they needed to know it, according to His purpose.
Another very good reason that they will not be self-appointed is that almost no one in their right mind would volunteer for such a mission! That is not to say that God's two witnesses will not be in their right minds, they surely will, but they will have an ordeal to endure that will require a level of courage, and physical and psychological toughness, that very few people possess - or would ever want to. They will be two very intense individuals. (see Are The Two Witnesses Here Now?)
Down Without A Fight?
When Jesus Christ (see also The Logos) was sent by God the first time, it was for the purpose of being voluntarily sacrificed as a meek and humble "Lamb of God." When The Messiah returns however, it will be as an all-powerful, conquering "King of kings and Lord of lords" (Revelation 19:11-16). Genuine world peace will be enforced upon a sinful and violent humanity (see King Of The Mountain).
Prior to The Return Of Jesus Christ, when the day of their appointed martyrdom arrives, will God's two witnesses surrender to the enemies of God? Will they go down without a fight? Not a chance. "And when they shall have finished their testimony, the beast that ascendeth out of the bottomless pit shall make war against them, and shall overcome them, and kill them" (Revelation 11:7 King James Version). God's faithful and true two witnesses will go down, figuratively speaking, with "all guns blazing." When it comes to fighting the forces of Satan, God wouldn't have it any other way.
Fact Finder: What other two men, who were also given various miraculous powers, including over plagues and the weather, were the Old Testament's version of the "two witnesses"?
See also Moses and Aaron and The Ten Plagues