Charles Ellicott Commentary Revelation 11:5

"And if any man desireth to hurt them, fire proceedeth out of their mouth and devoureth their enemies; and if any man shall desire to hurt them, in this manner must he be killed." — Revelation 11:5 (ASV)

And if any man . . .—Better, And if anyone wills to injure them, fire goes forth out of their mouths, and devours their enemies: and if anyone wills to injure them, thus must he be killed. These have power to shut the heaven that the rain may not water (the earth) during the days of their prophesying; and they have power over the waters to turn them into blood, and to smite the earth with every plague as often as they will.

Again the Old Testament basis becomes evident; the histories of Elijah and Moses supply the illustration. The fire devouring their foes seems to allude to 2 Kings 1:10; like Elijah, they can close the heaven (1 Kings 17:1); like Moses, they can turn water into blood and summon down every plague (Exodus 7:20 and following).

These last characteristics remind us of the spirit and power of Moses and Elias, but we must not forget what has gone before: the witnesses are like olive trees and lights. In them is concentrated grace, light, and power; their witness recalls the great features of various Old Testament teachers and leaders; they display the light of truth, and men cannot oppose or injure them with impunity; they wield a power which it is not safe to provoke.

As from the mouths of the great Sixth Trumpet host there went forth fire and smoke and brimstone to kill the third part of mankind, so out of the mouths of these witnesses there goes forth a purer, but mightier flame. (Compare Psalms 18:8.) We may compare the sword out of the mouth of Christ (Revelation 1:16), and the promise to Jeremiah (Jeremiah 5:14), Behold I will make my words in thy mouth fire and this people wood, and it shall devour them. The word which is like a sword to lay bare man to himself may become a consuming fire to those who resist or oppose it.

The witnesses for God are thus armed with a spiritual might; for that word which, when accepted and lived by, brings peace, when rejected causes pain and danger. Thus often do the things which might have been for people's peace become an occasion for falling; the stone which, used and built into the life, becomes a precious cornerstone and immovable foundation, grinds to powder those upon whom it falls. So it is with these witnesses: they come to witness for principles that would make the world a Paradise once more.

The world, which casts away their words, will find them come back with scorching force; just as the breath of God gives life and beauty to the world, and power to people's hearts and lives (Psalms 104:30; John 20:22), yet with that same breath of His lips does He slay the wicked (Isaiah 11:4).

Some have thought that there will be a time when witnesses for God will be raised up who will work literal wonders such as these. It is not for us to say that this will not be the case: all prophecy may take a sharper and clearer meaning as the times of the end draw near; but, meanwhile, it is necessary for us to remember that the very power of truth is such that, when rejected, it can and does avenge itself by shutting heaven over our head, and making all the fresh rivulets of life’s purest pleasures loathsome as blood to the sensualized and perverted heart.