Joel was second of twelve minor prophets in the Old Testament.¹ He may have prophesied in Jerusalem² during the reign of King Uzziah as early as 800 BC.³ Thus, he was a likely contemporary of Isaiah, Hosea, and Amos.⁴ If this dating is correct, Joel was the first to reveal specific details about the Second Coming,⁵ and other prophets built on his words and his symbolic imagery.⁶

Joel's prophecies are highly significant because the angel Moroni quoted them to Joseph Smith on the night of September 21, 1823, and told him that Joel's prophecies were about to be fulfilled.⁷ Joel prophesied that God's spirit would be poured out in a Pentecostal manner when the gospel was restored in the latter days.⁸ This spiritual outpouring was to be generally felt among all people in the last days as foretold in Joel 2:28-29.⁹ Joel predicted that signs in the heavens and in the earth will accompany the wars that precede and accompany the Second Coming in Joel 2:30-31.¹⁰ He also prophesied in Joel 2:32 that during the final Abomination of Desolation at the Second Coming,¹¹ Israel will be protected on mount Zion (New Jerusalem),¹² and the Jews will be protected at Old Jerusalem.¹³ Moroni specifically quoted Joel 2:28-32 to Joseph Smith,¹⁴ which are a preface to Joel's more detailed prophecies about the last days in Joel chapter 3.¹⁵

Joel 3 begins with the words in those days, and in that time to describe events that are certain to occur at a set date and time before and at the Second Coming.¹⁶ Among these events, Joel foresaw the battle of Armageddon¹⁷ when the Lord will "gather all nations, and will bring them down into the valley of Jehoshaphat."¹⁸ Jehoshaphat was a righteous king in the southern kingdom of Judah.¹⁹ His name means the Lord (Jehovah) judges.²⁰ Joel symbolically equates Jehoshaphat's name²¹ with the valley of decision,²² where Christ will judge and destroy the wicked nations of the earth that gather against Old Jerusalem during Armageddon.²³ The Valley of Jehoshaphat probably²⁴ begins at the Kidron Valley in Jerusalem, located between the east side of the temple mount and the west side of the mount of Olives.²⁵ The complete battleground, however, extends at a minimum from the Kidron Valley to the Valley of Megiddo.²⁶ This area has a long history of decisive battles,²⁷ which foreshadow the future battle of Armageddon.²⁸ Megiddo is part of the Plain of Esdraelon (Ez-draw-E-lawn), north of Jerusalem.²⁹ Massive armies numbering in the millions of millions³⁰ will gather in this area to engage in the battle of Armageddon.³¹ Jerusalem is both the center place for the battle and its primary objective.³²

Through the prophet Joel, the Lord invites and even commands³³ the gentile nations to gather themselves in the Valley of Jehoshaphat to fight the Lord's mighty ones.³⁴ The mighty ones include the Two Witnesses in Jerusalem that will have the sealing power,³⁵ and also Christ at the time of his Second Coming.³⁶ The Gentiles will fight the battle of Armageddon as a holy war,³⁷ and even the weakest among them will eagerly beat their plowshares into swords to participate.³⁸

Joel foresaw the latter-day gathering of Jews to Jerusalem from the lands of their captivity, saying: "I shall bring again the captivity of Judah and Jerusalem."³⁹ These words describe the blessed condition of the Jews as they return to Jerusalem in the modern era to rebuild their capital city and their nation.⁴⁰ However, Joel's words have a sinister message because the Jews, according to this prophecy, are essentially gathering to the very battlegrounds of the future Armageddon where they will be combatants.⁴¹ The Gentiles will besiege Jerusalem and afflict the Jews during the Great Tribulation of the last 3½ years of Physical Armageddon.⁴² However, the Jews will be preserved by the power of the Two Witnesses who will minister at Jerusalem until their deaths just 3½ days before the Second Coming.⁴³

When Christ steps foot on the mount of Olives at the Second Coming,⁴⁴ a righteous remnant of the Jews will be freed from their Gentile captors as a further fulfillment of Joel's prophecy that Christ shall bring again the captivity of Judah and Jerusalem.⁴⁵ The Jewish remnant will be freed physically from their Gentile oppressors.⁴⁶ But they will also be freed spiritually from their captivity of unbelief as they accept Christ‒their Redeemer‒at and after the Second Coming.⁴⁷ Christ will then plead for the righteous remnant of his people⁴⁸ as their advocate and judge.⁴⁹

When Christ appears on Olivet and pleads in favor of his people, he will also execute judgement upon the gentile nations.⁵⁰ They will be destroyed as the final Abomination of Desolation comes to an end.⁵¹ The gathered Gentiles will be destroyed because their iniquity will then be full.⁵² In the words of Joel, the wicked will be harvested like grapes that are reaped with a sickle and crushed in the winepress.⁵³ Christ will recompense the Gentiles with the same desolations that they inflict upon the Jews and all of Israel.⁵⁴ The Gentiles will be destroyed for taking the land of promise by force and scattering Israel,⁵⁵ for desecrating the temple in Jerusalem,⁵⁶ for enslaving the Israelites,⁵⁷ and for stealing their property.⁵⁸