“And I will give power unto my two witnesses, and they shall prophesy a thousand two hundred and threescore days, clothed in sackcloth.”
King James Version (KJV)
11:3 And I - Christ. Will give to my two witnesses - These seem to be two prophets; two select, eminent instruments. Some have supposed (though without foundation) that they are Moses and Elijah, whom they resemble in several respects. To prophesy twelve hundred and sixty days - Common days, that is, an hundred and eighty weeks. So long will they prophesy, (even while that last and sharp treading of the holy city continues,) both by word and deed, witnessing that Jesus is the Son of God, the heir of all things, and exhorting all men to repent, and fear, and glorify God. Clothed in sackcloth - The habit of the deepest mourners, out of sorrow and concern for the people.
Re 11:3 THE TWO WITNESSES. I will give [power] unto my two witnesses. These two witnesses are witnesses for the Lord. They shall prophesy a thousand two hundred [and] threescore days. They shall bear witness for 1260 days, the forty-two months the Holy City is trodden down (Re 11:2). During this time they shall prophesy clothed in sackcloth, a symbol of sorrow and mourning. It implies that these witnesses shall be in tribulation during the period named.