And I will give power unto my two witnesses, and they shall prophesy a thousand two hundred and threescore days, clothed in sackcloth. These are the two olive trees, and the two candlesticks standing before the God of the earth. (Revelation 11:3-4)
The passage above does not clearly identify who the two witnesses are. However, the following verse was a promise given to the apostle John as he wrote the book of Revelation.
And he said unto me, Thou must prophesy again before many peoples, and nations, and tongues, and kings. (Revelation 10:11)
Tradition states that John was exiled to Patmos by the Emperor Domitian around 95 AD and then returned to his home in Ephesus 18 months later. John was probably in his 90s at this point, and there is no Biblical or historical evidence that John prophesied “before many peoples, and nations, and tongues, and kings” after he left Patmos. However, the two witnesses will do exactly that. Since this promise must be fulfilled, it is very possible that John is one of the two witnesses.
God made a similar promise to the prophet Daniel:
But go thou thy way till the end be: for thou shalt rest, and stand in thy lot at the end of the days. (Daniel 12:13)
The Hebrew word translated lot can also mean portion, or “thing assigned by casting lots”. So it appears that Daniel will rest and then stand to fulfill his assignment in the “end of the days”. It is possible that Daniel is the second witness.
The ministry of these two witnesses is described in this passage:
And if any man will hurt them, fire proceedeth out of their mouth, and devoureth their enemies: and if any man will hurt them, he must in this manner be killed. These have power to shut heaven, that it rain not in the days of their prophecy: and have power over waters to turn them to blood, and to smite the earth with all plagues, as often as they will. 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. And the same hour was there a great earthquake, and the tenth part of the city fell, and in the earthquake were slain of men seven thousand: and the remnant were affrighted, and gave glory to the God of heaven. (Revelation 11:5-13)