In the first part of this chapter, Joel has set up a picture, a picture in which the people have been in open and gross rebellion against God, and God has sent a serious plague upon them. Then the prophet calls upon the people to repent of their wickedness and to change their hearts, not to simply provide outward display; he has called them to get real and right with God. Now in these verses it is God’s turn to respond, and what a response!
In verse 18 we see that God became “jealous” for His land and took pity on His people in their repentance. What we see in v. 18 is the depth of God’s love for His people. Did you notice the change in tense? Joel is speaking in the past tense which clues us in to the fact that this is archetype; it is for all times and peoples.
God takes away the “locusts”, takes away their suffering and once again provides for the needs of His people. Now that they have turned away from their rebellion (sin) He provides them with abundant blessings. Take careful notice: By the time we come to the end of the passage, the people have been restored so completely it is as if they had never sinned. Of course that should come as no surprise, for I told you in the beginning that Joel’s is a messianic prophecy. God is once again dwelling with His people in a very special way, now that the people have been delivered from judgment.
These verses enable us to nail down Joel’s discussion as being without question messianic in nature, for they are quoted by Peter in his address to the crowds on the day of Pentecost (Acts 2:17-21). Peter as you know, told the crowd that day after the Holy Spirit had come to the Apostles, the pouring out of the Spirit at that time, was exactly what Joel had foretold. Jesus Messiah had come to earth bringing the good news of reconciliation between God and Man, and had then willingly gone to the cross so that His blood could be shed to take away the sins of Mankind; this is what Joel was alluding to in the previous verses. After that, came Pentecost and the pouring out of the Spirit thereby giving a sign to all humanity that God had carried out His purpose.
Now we can easily see why the crowd was so quickly impacted by Peter’s address to them, for they had come to recognize that on that very day, God was doing His greatest work; redeeming humanity.