This pericope contains a call to the nations to prepare for war (vv. 9-11), a statement by the Lord (vv. 12-13), and a description of the battle site (vv. 14-16).
3:9-11 The Lord issued a call to war. The nations should prepare for a great battle by beating their plowshares into swords and their pruning hooks into spears.34The weak should "psych"themselves up in preparation. The nations should hurry and assemble (cf. Zech. 12:9). Joel also called on Yahweh to bring down His mighty army of angelic warriors to engage the enemy of His people (cf. Deut. 33:2-3; 2 Kings 6:17; Ps. 68:17; 103:19-20; Zech. 14:5).
3:12-13 The Lord urged the nations to rouse themselves and to assemble in the valley of Jehoshaphat (cf. v. 2) because it was there that He would sit in judgment on them. He compared this judgment to harvesting grain with a sickle and to treading grapes in a vat (cf. Isa. 17:5; 63:1-6; Rev. 14:14-20). As grapes squirt juice when trodden, so the nations will give up the wickedness with which they have been full (cf. 2:24).
This scene of divine warfare must correspond to the battle of Armageddon at the end of the Tribulation (cf. Rev. 14:14-20; 16:16; 19:11-21). The judgment of the nations following Christ's second coming (Matt. 25:31-46) will not involve warfare.
3:14-16 The prophet viewed many multitudes in the valley, which he now referred to as the valley of decision because there God will make a decision concerning their fate. This day of the Lord was near from his perspective, which for the prophets was often deceiving due to their foreshortened view of the future. He saw the celestial phenomena again that signaled doom (cf. 2:10, 31). Lion-like Yahweh roared from Zion announcing His attack on the nations, and everything trembled (cf. 2:10-11; Rev. 16:16, 18). For His own people, however, He proved to be a refuge and a stronghold.
3:17 Yahweh's victory will demonstrate to His people that He is indeed Israel's covenant God and that His special place of abode is Mt. Zion (cf. 2:27). After this battle Jerusalem will be the holy city, set apart entirely for God's people and no longer defiled by foreign invaders.
