The statement that sons and daughters shall prophesy has generally been understood as a reference to the greater measure and abundance of the Spirit’s work in the new covenant. In the past the Spirit was primarily involved with prophets and kings; now he will be given to many more people: sons and daughters, young men and old men, male and female servants. All those who belong to God, no matter their social class or status, will have the Spirit dwelling within them. Every Christian will be equipped and prepared for works of service, specifically the work of testifying to Christ.
Peter’s interpretation is helpful to us especially when it comes to understanding other prophecies that speak about the Spirit. If Joel is fulfilled in these last days, then those other prophecies must be fulfilled as well. What is said about the Spirit in Ezekiel, Isaiah, and Jeremiah therefore applies to the time in which we live, the time of the new covenant. But if that is the case, what do we do when the prophets seem to say things that are not realized? Jeremiah, for example, mentions that in the new covenant everyone will know the Lord—from the least to the greatest. There will be no need to teach your neighbour. Joel says that we will all prophesy—sons and daughters, young and old. There will be dreams and visions for everyone.
Understood from a literal point of view this would mean that there is no longer any need for ministers to proclaim God’s Word or elders to rule over the church. If we can all prophesy and know the Lord, if God speaks to us in dreams and visions, then we do not need anyone to teach us about him. But that is not the pattern we see in the New Testament, not even in Acts. The apostles appoint elders in the churches, and they explain God’s Word to his people. The Spirit has come, but we are not prophets in quite the same way that prophets were known in the old covenant. We testify that Jesus is the Christ; we do not look for dreams and visions about him.
17 “‘And in the last days it shall be, God declares, that I will pour out my Spirit on all flesh, and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams;