The Holy Bible, Revelation 11:2-13

2 But the court which is without the temple leave out, and measure it not; for it is given unto the Gentiles: and the holy city shall they tread under foot forty and two months.

3 And I will give power unto my two witnesses, and they shall prophesy a thousand two hundred and threescore days, clothed in sackcloth.

4 These are the two olive trees, and the two candlesticks standing before the God of the earth.

5 And if any man will hurt them, fire proceedeth out of their mouth, and devoureth their enemies: and if any man will hurt them, he must in this manner be killed.

6 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.

7 And when they shall have finished their testimony, the beast that ascendeth out of the bottomless pit shall make war against them, and shall overcome them, and kill them.

8 And their dead bodies shall lie in the street of the great city, which spiritually is called Sodom and Egypt, where also our Lord was crucified.

9 And they of the people and kindreds and tongues and nations shall see their dead bodies three days and an half, and shall not suffer their dead bodies to be put in graves.

10 And they that dwell upon the earth shall rejoice over them, and make merry, and shall send gifts one to another; because these two prophets tormented them that dwelt on the earth.

11 And after three days and an half the Spirit of life from God entered into them, and they stood upon their feet; and great fear fell upon them which saw them.

12 And they heard a great voice from heaven saying unto them, Come up hither. And they ascended up to heaven in a cloud; and their enemies beheld them.

13 And the same hour was there a great earthquake, and the tenth part of the city fell, and in the earthquake were slain of men seven thousand: and the remnant were affrighted, and gave glory to the God of heaven.

The Book of Mormon, 2 Nephi 8:19-20

19 These two sons are come unto thee, who shall be sorry for thee–thy desolation and destruction, and the famine and the sword–and by whom shall I comfort thee?

20 Thy sons have fainted, save these two; they lie at the head of all the streets; as a wild bull in a net, they are full of the fury of the Lord, the rebuke of thy God.

The Doctrine and Covenants, Section 133:58

58 To prepare the weak for those things which are coming on the earth, and for the Lord’s errand in the day when the weak shall confound the wise, and the little one become a strong nation, and two shall put their tens of thousands to flight.

The Doctrine and Covenants, Section 77:15

15 Q. What is to be understood by the two witnesses, in the eleventh chapter of Revelation? A. They are two prophets that are to be raised up to the Jewish nation in the last days, at the time of the restoration, and to prophesy to the Jews after they are gathered and have built the city of Jerusalem in the land of their fathers.

Journal of Discourses, Orson Pratt 16:43

We might bring up, also, the declaration of John in relation to the two witnesses who are to prophesy about that period. They are to prophesy three and a half years, and their field of labor will be Jerusalem, after it shall have been rebuilt by the Jews. By means of their prophecies and the power of God attending them, the nations who are gathered together against Jerusalem will be kept at bay, these Prophets will hold them in check by their faith and power. By and by these nations overcome the two witnesses and, having finished their mission, they are slain, and their bodies will lie three days and a half in the streets of the city. Then a great earthquake will take place, and these two witnesses will be caught up to heaven.

Journal of Discourses, Orson Pratt 18:7

After awhile, when tens of thousands of them have gathered and rebuilt their Temple, and reestablished Jerusalem upon its own heap, the Lord will send forth amongst them a tremendous scourge. What will be the nature of that scourge? The nations that live in the regions round about Jerusalem will gather up like a cloud, and cover all that land round about Jerusalem. They will come into the Valley of Jehoshaphat, east of Jerusalem, and they will lay siege to the city. What then? The Lord will raise up two great Prophets, they are called witnesses, in the Revelation of St. John. Will they have much power? Yes, during the days of their prophesying they will have power to smite those who undertake to destroy them, and until their testimonies are fulfilled they will be able to keep at bay all those nations besieging Jerusalem, so that they will not have power to take that city. How long will that be? Three and a half years, so says John the Revelator. If any man hurt them, they shall have power to bring upon that man, nation or army, the various plagues that are there written. They will have power to smite the earth with plague and famine, and to turn the rivers of water into blood. And when they have fulfilled their prophecy, then the nations that have been lying before Jerusalem so long, waiting for an opportunity to destroy the city, will succeed in killing these two Prophets, and their bodies, says John’s revelations, will lie in the streets of Jerusalem three days and a half after they are killed. What rejoicing there will be over the death of these men! Those who have been waiting so long and anxiously for this to take place, will no doubt send gifts one to another, and if the telegraph wires are not destroyed, they will telegraph to the uttermost parts of the earth that they have succeeded in killing the two men who had so long tormented them with plagues, turning the waters onto blood, etc. But by and by, right in the midst of their rejoicing, when they think the Jews will now certainly fall a prey to them, behold there is a great earthquake, and in the midst of it these two Prophets rise from the dead, and they hear a voice up in the heavens saying–”Come up hither;” and they immediately ascend in the sight of their enemies. What next? Notwithstanding all this, those nations will be so infatuated, and so determined to persecute the people of God–as much so as Pharaoh and his army in ancient days–that they will say–”Come, now is the time to pitch into the Jews and destroy them.” And they will commence their work of destruction, and they will succeed so far as to take one half the city, and while they are in the very act of destroying Jerusalem, behold the heavens are rent, and the Son of God with all the heavenly hosts appears, and he descends and rests upon the summit of the Mount of Olives, which is before Jerusalem on the east. And so great will be the power of God that will then be made manifest, that the mountain will divide asunder, half going towards the south, and half towards the north, producing a great valley going east and west, from the walls of Jerusalem eastward.

New Testament Student Manual, Revelation 11