"They are 'the two olive trees' and the two lampstands, and 'they stand before the Lord of the earth.'[a] If anyone tries to harm them, fire comes from their mouths and devours their enemies. This is how anyone who wants to harm them must die. They have power to shut up the heavens so that it will not rain during the time they are prophesying; and they have power to turn the waters into blood and to strike the earth with every kind of plague as often as they want." (Revelation 11.4-6)✞
Moses was the primary law giver and Elijah was the premier prophet in the Old Testament. These two greats appeared with Jesus at the Transfiguration but here they are witnesses on earth like two olive trees or two lamp stands. In the prophecy of Zechariah 4, the prophet sees two olive trees also. In Zechariah 4.1-3 we read, "Then the angel who talked with me returned and woke me up, like someone awakened from sleep. He asked me, 'What do you see?' I answered, 'I see a solid gold lampstand with a bowl at the top and seven lamps on it, with seven channels to the lamps. Also there are two olive trees by it, one on the right of the bowl and the other on its left.'" The angel identifies the two olive trees in Zechariah 11.14, "These are the two who are anointed to [or "two who bring oil and"] serve the Lord of all the earth." These two olive trees are symbols of the two witnesses. They are clothed in sackcloth, a very coarse, rough fabric woven material usually made from goat's hair or from flax or hemp, often symbolizing mourning. It was occasionally worn as a prophet's clothing as a sign of submission. In Christianity, the tradition of wearing a sack-cloth hair shirt, continued as a self-imposed means of mortification of the flesh often worn during Lent, especially on Ash Wednesday, Good Friday, and other Fridays of the Lenten season. Sack-cloth could have been an empty sack with holes cut in for the head and arms or otherwise a loin-cloth. Aramean soldiers sought mercy from the King of Israel in 1 Kings 20.31, "wearing sack-cloth around their waists and ropes around their heads, they went to the king of Israel and said, 'Your servant Ben-Hadad says: "Please let me live."'" It is interesting that Isaiah wore nothing else but sack-cloth as in Isaiah 20.2, "at that time the Lord spoke through Isaiah son of Amoz. He said to him, 'Take off the sack-cloth from your body and the sandals from your feet.' And he did so, going around stripped and barefoot. Then the Lord said, 'Just as my servant Isaiah has gone stripped and barefoot for three years, as a sign and portent against Egypt and Cush,[or the Upper Nile Region] so the king of Assyria will lead away stripped and barefoot the Egyptian captives and Cushite exiles, young and old, with buttocks bared to Egypt's shame.'"
Moses and Elijah were given miraculous powers by God. Elijah closed the sky so that it did not rain. Moses turned the water into blood as in Exodus 7.19, "The LORD said to Moses, 'Tell Aaron, "Take your staff and stretch out your hand over the waters of Egypt over the streams and canals, over the ponds and all the reservoirs and they will turn to blood." Blood will be everywhere in Egypt, even in vessels of wood and stone.'" Moses used the miracles and plagues before the Pharaoh in Egypt in order to persuade him to let the people of Israel leave Egypt and journey to the promised land.✞