Traditionally, the book of Joel has been regarded as one of the earliest of the writing prophets. The fact is, however, there is little in this book to help us know when it was written. A locust plague serves as the backdrop for the prophecy, along with oppression from enemies such as the Phoenicians (Tyre) and Philistines. There are references to these things in Amos, whose book occurs about this time period. The book is written to Judah.
The spiritual circumstances recounted in the book are those which could have been common to any period of the minor prophets (called “minor” because their books are so short). As if foreign oppression wasn’t enough, Judah is suffering from a devastating locust plague that has brought famine on the land, but this is not a “natural disaster.” This plague has been brought on by the Lord Himself because of Judah’s sins.
If His people will repent, God promises a level of blessing not seen at any other time in history: He will place His Spirit on His people. The Spirit is God’s empowering presence to enable God’s people to do and be what God has decreed for them, and Joel’s promise inaugurates a new hope for His people.
But it will not happen, because God’s people, for all the reform of Joash, still have not returned to God. The “form” of Israel’s religion may be restored, but the function of it in the heart of God’s people will not happen.
When God’s spirit does come, it is during the Feast of Weeks after the Passover of Jesus’s death and resurrection, and it christens a new age in which the people of God will be composed not just of descendants of Jacob, but of all people who “call on the name of the Lord.”