This section begins with the words "And it shall come to pass afterward", which is after the beginning of the millennium, when the LORD will be in the midst of Israel, as mentioned in the previous verse.
Recapitulating, the prophecy of Joel began by telling us of a frightful locust plague, which was then compared to a future catastrophe later identified as the Day of the Lord. The Day of the Lord will begin with the Tribulation period, after which Christ will come and establish His Kingdom on the earth. In verse 27 we learn that the Lord at that time will be in the midst of Israel.
According to Dr. Charles L. Feinberg, a Jewish Christian and Hebrew scholar, "Verses 28 to 32 form chapter 3 in the Hebrew text; and chapter 3 in the English translations is chapter 4 in the original. No one will be inclined to doubt that the disclosure of truth in Joel 2:28-32 is of sufficient importance to warrant its appearing in a separate chapter."
It is of great importance to note the time of fulfilment indicated in this passage, because the quotation of this verse given by Peter in Acts 2:16-21 on the day of Pentecost is misinterpreted by some people. Peter used this prophecy as an answer to the cynical, the unbeliever and the mocker. His purpose for quoting it was to show that what happened at that time was similar to that which had been prophesied by Joel to happen in the last days. "That is that," means this is similar to or this is like that. He didn't say that it was the actual fulfilment of the prophecy.
Those people could only think of drunkenness as an explanation for the fact that everyone heard the disciples speak the wonderful works of God in his own language. But Peter reminded them of this prophecy right through to the end, making it obvious that he was not attempting to say it had been fulfilled. No one can claim that on the Day of Pentecost the moon was turned to blood or that the sun was turned to darkness, nor were there wonders of heaven above and signs in the earth beneath, nor was there blood and fire and a vapour of smoke. It is still going to come to pass in God's timing.
As the first of the writing prophets, Joel introduced the concept of the "day of the LORD", and told us something of what will be taking place during that period. He emphasised the fact that it will begin with the darkness of the Great Tribulation period (our Lord Jesus gave it that name).
The prophet Hosea, explains (writing later): "Afterward the children of Israel shall return and seek the LORD their God and David their king. They shall fear the LORD and His goodness in the latter days." The latter days are identified as that time at the close of the Great Tribulation period which ushers in the Kingdom by the coming of Christ to the earth, which is the beginning of the Millennium. This leads us to conclude that Joel referred to a very definite period of time, that this prophecy is to be fulfilled during the Day of the Lord, after the night of the Great Tribulation period. Then God will pour out His Spirit upon all flesh.
When that happens, the younger generation shall prophesy and see visions and the old men shall dream dreams: these will be supernatural manifestations. Other references to the outpouring of the Holy Spirit in the last days are found in later prophecies, for example:
"… Until the Spirit is poured upon us from on high, and the wilderness becomes a fruitful field, and the fruitful field is counted as a forest. Then justice will dwell in the wilderness, and righteousness remain in the fruitful field. The work of righteousness will be peace, and the effect of righteousness, quietness and assurance forever. My people will dwell in a peaceful habitation, in secure dwellings, and in quiet resting places…" (Isaiah 32:15-18). This refers to the Kingdom which is coming on the earth, and the pouring out of the Spirit has reference to the Millennium. Of course none of the prophets spoke of the church age, as it had not yet been revealed; all of them spoke of the last days in reference to the nation Israel.
"I will put My Spirit within you and cause you to walk in My statutes, and you will keep My judgements and do them. Then you shall dwell in the land that I gave to your fathers; you shall be My people, and I will be your God." (Ezekiel 36:27-28). It concerns a particular people and a particular land: Israel. It is also a particular period of time when God will pour out His Spirit.
"'I will put My Spirit in you, and you shall live, and I will place you in your own land. Then you shall know that I, the LORD, have spoken it and performed it,' says the LORD." ( Ezekiel 37:14).
"'And I will not hide My face from them anymore; for I shall have poured out My Spirit on the house of Israel,' says the Lord GOD." (Ezekiel 39:29).
Zechariah was one of the last of the writing prophets. We read: "And I will pour on the house of David and on the inhabitants of Jerusalem the Spirit of grace and supplication; then they will look on Me whom they pierced. Yes, they will mourn for Him as one mourns for his only son, and grieve for Him as one grieves for a firstborn…" (Zechariah 12:10).
Verses 30 and 31 go back in time to before the coming of the great and awesome day of the LORD. As often happens in the Bible, events aren't given in strict chronological order, the subject matter being of more importance than obedience to the sequence of time. Joel announces wonders in the heavens and in the earth, like a blackout as a result of atmospheric pollution, to occur before the tribulation of the last days.
Later prophecies also inform of world wars (Matthew 24:4-8), the forming of the nation of Israel (Ezekiel 20:33-38), the attempted invasion of Israel (Ezekiel 38:1 - 39:16), peace among nations (1 Thessalonians 5:1-3, world government being broken into ten kingdoms (Daniel 7:24), the rise of the beast, or antichrist (11 Thessalonians 2:1-3), the seven year covenant between him and the nation of Israel (Daniel 9:27), the return of Elijah (Malachi 4:5-6), the rapture of the church of Christ (1 Thessalonians 4:16-17, etc.).
The final verse of this section reads that whoever calls on the name of the LORD shall be saved: for in Mount Zion and in Jerusalem there shall be deliverance. In those very early days of prophecy the message of salvation in the name of the Lord was announced - nearly a thousand years later this became clear when the Lord Jesus, the Messiah, came into the world and gave his blood so that all those who trust in His name may be saved.
Peter used Joel's prophecy to answer those who were mocking the wonder of the Gospel being preached in various languages unknown to the speakers. The subject of Peter's discourse, however, was the resurrection of the Lord Jesus Christ.
Referring to Psalm 16:8-10, which prophesies the resurrection of Christ, Peter applied it to Christ: "This Jesus, God has raised up, of which we are all witnesses. Therefore being exalted to the right hand of God, and having received from the Father the promise of the Holy Spirit, He poured out this which you now see and hear." (Acts 2:32-33). Peter's exhortation to those people was "Be saved from this perverse generation."
From Joel's prophecy and many other passages, one is led to think that the greatest time of salvation is yet in the future. Spurgeon said that he believed God would win more to Himself than would be lost. When Christ comes to the earth to establish His Kingdom, there is going to be the greatest time of individuals turning to God that the world has ever seen.
Also during the Tribulation period there will be a great turning to the Lord, probably much greater than there has been during the church age. There will be great persecution, and the multitude of believers who will become martyrs during that time is mentioned in Revelation: "… a great multitude which no one could number, of all nations, tribes, peoples, and tongues, standing before the throne and before the Lamb, clothed with white robes … these are the ones who come out of the great tribulation, and washed their robes and made them white in the blood of the Lamb." (Revelation Rev 7:9-14).
From the time of the rapture of the church, however, it appears that the Holy Spirit will be withdrawn (2 Thessalonians 2:6-7) until the time of the new outpouring at the beginning of the millennium, which is being prophesied by Joel.
28 "And it shall come to pass afterward that I will pour out My Spirit on all flesh; your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions.
29 And also on My menservants and on My maidservants I will pour out My Spirit in those days.
30 "And I will show 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 coming of the great and awesome day of the LORD.
32 And it shall come to pass that whoever calls on the name of the LORD shall be saved. For in Mount Zion and in Jerusalem there shall be deliverance, as the LORD has said, among the remnant whom the LORD calls.