Book of The Revelation of Jesus Christ
Charles Caldwell Ryrie, "Note on Two Witnesses"
Revelation Chapter 11
Charles Caldwell Ryrie in his book "Revelation" only describes these two men as two witnesses whose 1,260 day ministry comes to a remarkable conclusion when "The Beast" ascends from the bottomless pit.
The character of their ministry, referenced to Zechariah 4:3, is that of anointed ones and light bearers of the truth of God.
(1) Their ministry, designed to remind the nation of Israel of the Prophets (namely Moses and Elijah - as the witness's ministry directly parallels Moses and Elijah), (2) their death in Jerusalem, now referred to as Sodom, and (3) their resurrection, three and a half days later, is obviously designed to represent the Prophets from Aaron to Jesus Christ.
Many of the other sources I read try to make the reference to the two witnesses portray Moses and Elijah. The references to the miraculous abilities to (1) kill their enemies with fire, (2) keep it from raining, (3) turn waters to blood, (4) and bring plagues upon the earth, are plainly reminiscent of Elijah and Moses. However these other sources make great point of going back over the words of John the Baptist in his explanation of whether or not he was Elijah (John 1:19-21). One went so far as to say that if John the baptist has been received as Elijah he would have become Elijah by their faith.
These witnesses will be put through death (in an attempt to prove the power of the Beast) before their miraculous resurrection (thwarting the power of the Beast) is their ultimate witness to The Lord Jesus Christ to whom they have been giving witness to the Nation of Israel. Both Elijah and Moses were loved ones of God, and loved ones on a much higher scale than most of humanity can ever hope to achieve. Both Elijah have been seen at least once more at the mount of Transfiguration with Jesus Christ. The three of them fellowshipping. While it would seem to make a great impact to have both Elijah and Moses be these two witnesses one more time for all of the nation of Israel to see. It makes little religious, theological, or logical sense to make these loved ones of God re-affirm their position before God Almighty by requiring of them a second death experience (even though that death experience is short and ends in a Christ like resurrection and ascension.
However, on the other side of the second death issue, those who were released from their tombs upon the death of Jesus Christ surely had to re-experience death and return to their graves, so too did Lazarus, the trusted friend of Jesus Christ, have to return to the grave after his miraculous return to life. These returns to life (however brief) are usually referred to as Restorations and not Resurrections. So, returning to life from the grave for a special mission or witness is not something without precedence.
For me the best over all answer would be very close, actually to our liberal friend who thought that John the Baptist would have become Elijah through "their faith," but with a few theological improvements. (1) These two witnesses certainly have powers that are reminiscent of both Elijah and Moses, strongly in fact. (2) These two witnesses certainly have a ministry that demonstrates the overcoming power and authority of God. (3) These two witnesses certainly have a witness that conclusively demonstrates from whom they were sent and that He is God Almighty and that the world system nor the beast can have final victory. With only these three evidences it would seem that the answer can be only one of two choices.
(1) The witnesses are the Prophets Elijah and Moses. Along with this conclusion one must understand that this means that God will be putting His two most loved humans, who are already in His presence, back through the degrading experience of life as mortals and subject them to humiliation and a terrible death for the purpose of His witness among the nation of Israel in those last days. This is certainly possible, but for me, violates even the very principles of why we Pre-millennialists believe that the Church, the very body of Christ, will not go through the Tribulation, i.e., the Bride of Christ should not suffer the ugly rampages of the tribulation, because of His love for Her. If He would not put His Bride through that, why then His two beloved.
(2) The witnesses are men brought into ministry that are so like Elijah and Moses that the point of their witness and ministry cannot be missed even by the worldliest of the Jews. That as that liberal said, they become Elijah and Moses in the hearts and minds of those who understand the sign. Hopefully to lead some to faith in Our Lord Jesus Christ, or to lead them deeper into the lostness of absolute rejection.
(1) Charles Caldwell Ryrie, Revelation, Everyman's Bible Commentary, Moody Press, Chicago, 1968