Revelation 11:3

And I will give [power] unto my two witnesses
By whom are meant, not Enoch and Elias, as some of the ancient fathers thought, who, they supposed, would come before the appearance of Christ, and oppose antichrist, and be slain by him, which sense the Papists greedily catch at; nor are the Scriptures, the two Testaments, Old and New, designed, though their name and number agree, and also their office, which is to testify of Christ; but then to be clothed in sackcloth, to be killed, and rise again, and ascend to heaven, are things that cannot so well be accommodated to them: but these witnesses intend the ministers of the Gospel and churches of Christ, who have bore testimony for Christ, and against antichrist, ever since he appeared in the world; and particularly the churches and ministers in Piedmont bid fair for this character; who were upon the spot when antichrist arose, always bore their protest against him, and were ever independent of the church of Rome, and subsisted in the midst of the darkness of the apostasy; and suffered much, and very great persecutions, from the Papists; and have stood their ground, and continue to this day; and have been like olive trees and candlesticks, imparting oil and light to others. Though they ought not to be considered exclusive of other ministers and churches, who also have bore, and still do bear a witness for Christ, and against the idolatries of the church of Rome: no two individual persons can be meant, since these witnesses were to prophesy 1260 days, that is, so many years, but a succession of ministers and churches; and these are called two, both on account of the fewness of them, and because the testimony of two is sufficient to confirm any matter; and it may be in allusion to the various instances of two eminent persons being raised up at certain periods of time, as Moses and Aaron, at the deliverance of the children of Israel out of Egypt; Caleb and Joshua, at their entrance into Canaan; Elijah and Elisha in the idolatrous times of Ahab; and Joshua and Zerubbabel at the rebuilding and finishing of the second temple. Now the Angel, and who is Christ, here promises that he will give something to these witnesses: some supply the words, "I will give it"; that is, the holy city, or the church, to them, to be taken care of and defended; others, "I will give" them a mouth and wisdom, which their adversaries shall not be able to resist, according to the promise in ( Luke 21:15 ) . We supply the words, "I will give power"; that is, authority to preach the Gospel, and strength to profess it, and to continue to bear a testimony to it, signified by prophesying; see ( 1 Corinthians 14:1 1 Corinthians 14:3 ) .

And they shall prophesy;
that is, "that they may prophesy"; which is supported by the Arabic and Ethiopic versions, the former rendering the words, "I will give to my two witnesses to prophesy", and the latter, "I will give in command to my two witnesses that they may prophesy"; the sense is, that Christ will give to them a mission and commission, sufficient authority, all needful gifts and grace, courage and presence of mind to preach his Gospel, to hold forth his word, and bear a testimony for him during the whole time of the apostasy, even

a thousand two hundred [and] threescore days;
that is, so many years, which, as before observed, is the date of the beast's reign, of the holy city being trodden under foot of the Gentiles, and of the church's retirement into the wilderness: it is observable, that the date of the beast's reign and tyranny is expressed by months, and the date of the church's being in the wilderness, and the prophesying of the witnesses, is signified by days; and the reason which some give is not despicable, as that the beast and his followers are the children of darkness and of the night, over which the moon presides, from whence months are, numbered; and the church and the witnesses are children of the day, over which the sun rules. The habit of these witnesses during their time of prophesying follows,

clothed in sackcloth;
expressive either of their outward state and condition, being poor, mean, and abject, while the followers of the beast are clad in silks, and live deliciously; or else of the inward frame of their minds, as mourning for the sad estate of the church of Christ, groaning under the tyranny and persecutions of antichrist.