Zechariah 4:2 likens God’s people, the Israelites, to the golden lampstand which testifies for God. God’s testimony needs the shining forth. To have this shining, there needs to be the burning; to have the burning, there needs to be a continuous supply of olive oil; and to have the olive oil, there needs to be the olive trees. Hence, there are two olive trees by the lampstand, one on its right and the other on its left, to produce the olive oil to supply the need of the lampstand that it may shine forth continually to dispel the darkness. The two olive trees are also called the two sons of oil (v. 14), and in Revelation 11 they are also called the two witnesses (vv. 3-4) and the two prophets (v. 10). The two olive trees symbolize Moses and Elijah, the two persons most used by God in the Old Testament to speak and testify for Him.
The writings that constitute the Old Testament are represented by the law and the prophets. The law of the Old Testament, which spoke and testified for God, was preached through Moses, who represents the law. The prophets of the Old Testament also spoke and testified for God, and they are represented by Elijah. Hence, the Old Testament is also called “the law and the prophets” (Luke 16:16). These two stand before the Lord of the earth testifying for God (Zech. 4:14; Rev. 11:4). Throughout the generations the law, represented by Moses, and the prophets, represented by Elijah, have been the testimony of God on the earth. The Bible also prophesies that Elijah will come again (Mal. 4:5; Matt. 17:11), indicating that he will be one of the two witnesses.
Moses died and his body was hidden by God (Deut. 34:5-6); Elijah was taken into heaven alive (2 Kings 2:11). God purposely did this so that Moses and Elijah might appear before the Lord Jesus in His transfiguration on the mount and converse with Him concerning His death (Luke 9:31), which was spoken of in the Old Testament (Luke 24:25-27, 44; 1 Cor. 15:3). They were preserved by God so that they could be the two witnesses in the great tribulation.
Revelation 11:5-6 speaks of two witnesses, saying, “If anyone desires to harm them, fire proceeds out of their mouth and devours their enemies...These have the authority to shut heaven that no rain may fall during the days of their prophecy; and they have authority over the waters to turn them into blood and to smite the earth with every plague as often as they desire.” Devouring the enemies with fire and shutting heaven that no rain may fall are very similar to what Elijah did (2 Kings 1:10-12; 1 Kings 17:1; Luke 4:25). Furthermore, turning water into blood and smiting the earth with every plague are very similar to what Moses did (Exo. 7:17, 19; 9:14; 11:1). This proves that the two witnesses are Moses and Elijah.