These have power to shut heaven, that it rain not in the days of their prophecy: and have power over waters to turn them to blood, and to smite the earth with all plagues, as often as they will; the power … the heaven … the waters … every plague (Revised Version).
The whole verse is descriptive of the powers entrusted to Moses and Elijah, and is intended to convey the idea that the power which supported them would likewise support the two witnesses. It is doubtful whether the meaning should be pressed further than this.
If we do so, it may, perhaps, be said that (in the words of Wordsworth) "if any one despises God's witnesses, they have the power, like Elias, to shut heaven, and exclude all who reject them. The dews of Divine grace are withheld from all who scorn them."
It is thus a fulfilment of our Lord's words, "Whosoever hath, to him shall be given, and he shall have more abundance: but whosoever hath not, from him shall be taken away even that he hath" (Matthew 13:12).
And again, besides the punishments which are finally to fall on the ungodly, it is the case that the rejection of God's will is followed on this earth by troubles which would be avoided were men to listen to the witness borne of him.