Prof. David Engelsma
The whole book is symbolic, the description of these two is clearly not to be taken literally. Revelation is repetitive.
Christ’s appointed witnesses speak God’s word as the two witnesses, the two olive trees and the two candlesticks.
Two witnesses is the number needed to testify to the truth (Deut.17:6, Matt.18:16 and II Cor.13:1).
Compare Zechariah 4.The two witnesses comprise the visible instituted true church composed of ministers and people who are all a wonder of grace. They as repentant people also call the godless to repentance, tormenting the wicked and the apostate church. The fire alludes to Jeremiah 5:14 which hardens and destroys the wicked. Their prayers also bring down divine judgment in the form of natural physical calamities as well as man-made violence and wars. Even though the antichristian kingdom appears to have been victorious it is actually the saints who win when Christ’s voice raises them from the dead (v12) to meet those alive at the time in the air with him.
Pre and post-millennial heresy have in common the error of excluding the church from suffering.
After a period when the false church serves antichrist, the beast turns against the whore and destroys her, tremendous natural calamities strike the antichristian kingdom which eventually destroys itself at Armageddon (c.f. II. Chron. 20).