There are a number of theories as to whom will fulfill the prophecy of the two witnesses of Revelation 11. One theory puts forth the angels Michael and Gabriel. Let's take a quick look at this possibility.
Michael is associated with Israel in both the Hebrew and Greek texts.
Now I have come to explain to you what will happen to your people in the future, for the vision concerns a time yet to come (Daniel 10:14)
At that time Michael, the great prince who protects your people, will arise. There will be a time of distress such as has not happened from the beginning of nations until then. But at that time your people—everyone whose name is found written in the book—will be delivered. (Daniel 12:1)
Yet Michael the archangel, in contending with the devil, when he disputed about the body of Moses, dared not bring against him a reviling accusation, but said, “The Lord rebuke you!” (Jude 1:9)
I believe what we see in the prophecy of Daniel connects Michael to the time of the tribulation ("a time of distress such as has not happened from the beginning of nations until then") and Israel ("your people").
Then I was given a reed like a measuring rod. And the angel stood, saying, “Rise and measure the temple of God, the altar, and those who worship there. But leave out the court which is outside the temple, and do not measure it, for it has been given to the Gentiles. And they will tread the holy city underfoot for forty-two months. And I will give power to my two witnesses, and they will prophesy one thousand two hundred and sixty days, clothed in sackcloth.” These are the two olive trees and the two lampstands standing before the God of the earth. And if anyone wants to harm them, fire proceeds from their mouth and devours their enemies. And if anyone wants to harm them, he must be killed in this manner. These have power to shut heaven, so that no rain falls in the days of their prophecy; and they have power over waters to turn them to blood, and to strike the earth with all plagues, as often as they desire. When they finish their testimony, the beast that ascends out of the bottomless pit will make war against them, overcome them, and kill them. And their dead bodies will lie in the street of the great city which spiritually is called Sodom and Egypt, where also our Lord was crucified. Then those from the peoples, tribes, tongues, and nations will see their dead bodies three-and-a-half days, and not allow their dead bodies to be put into graves. And those who dwell on the earth will rejoice over them, make merry, and send gifts to one another, because these two prophets tormented those who dwell on the earth.
The two witnesses are given power and given protection as they are given a ministry connected to the Temple and Altar (Rev 11:1-3). They are called "lampstands" (Rev 11:4). The conditions are said to mirror Sodom and Egypt (Rev 11:8). In Sodom. angels took on bodies and were the target of Sodomites. They had to seek shelter. So, it would seem if angels take on a body, they can "die."
While dead, Israel mourns them as the world rejoices. They are resurrected and then taken into heaven.
Now after the three-and-a-half days the breath of life from God [spirit] entered them, and they stood on their feet, and great fear fell on those who saw them. And they heard a loud voice from heaven saying to them, “Come up here.” And they ascended to heaven in a cloud, and their enemies saw them. In the same hour there was a great earthquake, and a tenth of the city fell. In the earthquake seven thousand people were killed, and the rest were afraid and gave glory to the God of heaven.
Obviously this is conjecture based on the possibility, but I think there is at least room to consider Michael (or angels) as the witnesses. Unless, I'm not considering something, it seems worthy of consideration. Michael and Daniel both being prominent in Daniel's prophecy of the 70 weeks and the time of Jacob's trouble (tribulation) along with Michael's appearance in the warning epistle of Jude in the Acts Age. There, Michael is seen as rebuking Satan in the name of the Lord. The context being Moses.
Yet Michael the archangel, in contending with the devil, when he disputed about the body of Moses, dared not bring against him a reviling accusation, but said, “The Lord rebuke you!”
A closer look at the lampstands should be undertaken as well. Angels being connected to the tribulation churches. The word angels can have a broader meaning, but we note it nonetheless. Staying in the Revelation:
The mystery of the seven stars which you saw in My right hand, and the seven golden lampstands: The seven stars are the angels of the seven churches, and the seven lampstands which you saw are the seven churches. (Revelation 1:20)
The olive tree imagery, as I see it, also points to Israel. Hosea 14 speaks of God restoring Israel as he did Hosea's adulterous wife. Israel will become "Ammi" (My people) again. I won't quote the whole chapter, but it's good reading.
Then said God, Call his name Lo-ammi: for ye are not my people, and I will not be your God.
Ezekiel speaks of the restoration of Israel when he will take their heart of stone and replace it with a heart of flesh. (Ezekiel 36:26). And they will again be his people. Jeremiah 31, Hebrews 8, Zechariah 8, Zechariah 12, etc.
Then you shall dwell in the land that I gave to your fathers; you shall be My people, and I will be your God. (Ezekiel 36:28)
His beauty shall be like an olive tree (Hosea 14:6b)
So, Michael and Gabriel could be considered here. Gabriel also appears in Daniel chapter 8 connected to the end times vision (which then connects to the Revelation and the gospels). Gabriel appears in Luke as well. This is what he prophecies to Mary, in part:
He [Jesus] will be great, and will be called the Son of the Highest; and the Lord God will give Him the throne of His father David. And He will reign over the house of Jacob forever, and of His kingdom there will be no end.”
This is connected to the Revelation and the restoration of the Kingdom in Israel and establishing of David's throne.
I, Jesus, have sent My angel to testify to you these things in the churches. I am the Root and the Offspring of David, the Bright and Morning Star. (Revelation 22:16)
The Son of David is connected to Israel and Gentiles have no claim to this title. The ministry of angels is also connected to Israel in many ways (especially Michael and Gabriel).
And behold, a woman of Canaan came from that region and cried out to Him, saying, “Have mercy on me, O Lord, Son of David!... But He answered her not a word... But He answered and said, “I was not sent except to the lost sheep of the house of Israel...” Then she came and worshiped Him, saying, “Lord, help me!” But He answered and said, “It is not good to take the children’s [Israel's] bread and throw it to the little dogs [Gentiles].”
Her request was granted when she acknowledged him only as Lord and took her place as a little dog below the children (the master). Her daughter was healed from a distance )as was the gentile Centurion's servant in Matthew 8).
And she said, “Yes, Lord, yet even the little dogs eat the crumbs which fall from their masters’ table.” Then Jesus answered and said to her, “O woman, great is your faith! Let it be to you as you desire.” And her daughter was healed from that very hour.
When a child of Abraham call on him the same way, the Lord responds quite differently.
And when he [the blind beggar] heard that it was Jesus of Nazareth, he began to cry out and say, “Jesus, Son of David, have mercy on me!” Then many warned him to be quiet; but he cried out all the more, “Son of David, have mercy on me!” So Jesus stood still and commanded him to be called. Then they called the blind man, saying to him, “Be of good cheer. Rise, He is calling you.” And throwing aside his garment, he rose and came to Jesus. So Jesus answered and said to him, “What do you want Me to do for you?”
Michael and Gabriel (as the angels in general) have a special ministry to Israel. Might they be called upon to be the witnesses to that nation in her time of great distress? It's worth considering.
The primary candidates put forward (for a number of reasonable and scriptural reasons) are Elijah, Enoch, and Moses. As with much of the prophecies concerning the last days and the time of Israel's testing, we stay in the arena of speculation trusting that God will do what is right and the remnant of Israel will recognize the witnesses sent to her.