The Holy Bible, Joel 2:28-32

28 And it shall come to pass afterward, that I will pour out my spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions:

29 And also upon the servants and upon the handmaids in those days will I pour out my spirit.

30 And I will shew wonders in the heavens and in the earth, blood, and fire, and pillars of smoke.

31 The sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the Lord come.

32 And it shall come to pass, that whosoever shall call on the name of the Lord shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as the Lord hath said, and in the remnant whom the Lord shall call.

The Doctrine and Covenants, Section 29:14

14 But, behold, I say unto you that before this great day shall come the sun shall be darkened, and the moon shall be turned into blood, and the stars shall fall from heaven, and there shall be greater signs in heaven above and in the earth beneath;

The Doctrine and Covenants, Section 34:9

9 But before that great day shall come, the sun shall be darkened, and the moon be turned into blood; and the stars shall refuse their shining, and some shall fall, and great destructions await the wicked.

The Doctrine and Covenants, Section 45:42

42 And before the day of the Lord shall come, the sun shall be darkened, and the moon be turned into blood, and the stars fall from heaven.

The Doctrine and Covenants, Section 88:87

87 For not many days hence and the earth shall tremble and reel to and fro as a drunken man; and the sun shall hide his face, and shall refuse to give light; and the moon shall be bathed in blood; and the stars shall become exceedingly angry, and shall cast themselves down as a fig that falleth from off a fig tree.

Zobell Jr., Albert L. (1971, July). A Modern Prophet at Ninety-Five. Ensign.

The words of the prophets are rapidly being fulfilled, but it is done on such natural principles that most of us fail to see it. Wonders in heaven and in the earth should be seen, and there should be fire, blood, and pillars of smoke. Eventually the sun is to be turned into darkness and the moon as blood, and then shall come the great and dreadful day of the Lord. Some of these signs have been given; some are yet to come. The sun has not yet been darkened. We are informed that this will be one of the last acts just preceding the coming of the Lord. One wonders if we are not now seeing some of the signs in heaven.

Conference Report, Gordon B. Hinkley, October 2001

The era in which we live is the fulness of times spoken of in the scriptures, when God has brought together all of the elements of previous dispensations. From the day that He and His Beloved Son manifested themselves to the boy Joseph, there has been a tremendous cascade of enlightenment poured out upon the world. The hearts of men have turned to their fathers in fulfillment of the words of Malachi. The vision of Joel has been fulfilled wherein the Lord declared: “And it shall come to pass afterward, that I will pour out my spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions: And also upon the servants and upon the handmaids in those days will I pour out my spirit. And I will shew wonders in the heavens and in the earth, blood, and fire, and pillars of smoke. The sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the Lord come. And it shall come to pass, that whosoever shall call on the name of the Lord shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as the Lord hath said, and in the remnant whom the Lord shall call” (Joel 2:28-32).