These have power to shut heaven - That is, so far as rain is concerned - for this is immediately specified. There is probably a reference here to an ancient opinion that the rain was kept in the clouds of heaven as in reservoirs or bottles, and that when they were opened it rained; when they were closed it ceased to rain. So Job, “He bindeth up the waters in his thick clouds, and the cloud is not rent under them,” Job 26:8. “Which the clouds do drop and distil upon man abundantly,” Job 36:28. “Who can number the clouds in wisdom? or who can stay the bottles of heaven?” Job 38:37; compare Genesis 1:7; Genesis 7:12; Genesis 8:2; 2 Kings 7:2. To shut or close up the heavens, therefore, is to restrain the rain from descending, or to produce a drought. Compare notes on James 5:17.
That it rain not in the days of their prophecy - In the time when they prophesy. Probably the allusion here is to what is said of Elijah, 1 Kings 17:1. This would properly refer to some miraculous power; but still it may be used to denote merely that they would be clothed with the power of causing blessings to be withheld from people, as if rain were withheld; that is, that in consequence of the calamities that would be brought upon them, and the persecutions which they would endure, God would bring judgments upon people as if they were clothed with this power. The language, therefore, it seems to me, does not necessarily imply that they would have the power of working miracles.
And have power over waters to turn them to blood - The allusion here is doubtless to what occurred in Egypt, Exodus 7:17. Compare the notes on Revelation 8:8. This, too, would literally denote the power of working a miracle; but still it is not absolutely necessary to suppose that this is intended. Anything that would be represented by turning waters into blood, would correspond with all that is necessarily implied in the language. If any great calamity should occur in consequence of what was done to them that would be properly represented by turning the waters into blood so that they could not be used, and that was so connected with the treatment which they received as to appear to be a judgment of heaven on that account, or that would appear to have come upon the world in consequence of their imprecations, it would be all that is necessarily implied in this language.
And to smite the earth with all plagues - All kinds of plague or calamity; disease, pestilence, famine, flood, etc. The word “plague” - πληγῇ plēgē - which means, properly, “stroke, stripe, blow,” would include any or all of these. The meaning here is, that great calamities would follow the manner in which they were treated, as if the power were lodged in their hands.
As often as they will - So that it would seem that they could exercise this power as they pleased.