The book of Joel was written between 770 and 870 BC, about 50 years before the Assyrians captured the northern ten tribe kingdom of Israel. God directed Joel to prophesy of Israel’s coming captivity because the nation was practicing idol worship, sacrificing their babies to idols, and disregarding the Lord’s commands (Jeremiah 19:5). Joel called for a fast to focus the people on their sinful behaviors and to then repent (Joel 2:12,13). Sadly, there is no biblical record that Israel did fast, but the historical fact of the Assyrian invasion (2 Kings 18:11-12) is evidence that Israel did not repent of their evildoing and did not mourn their conduct with a national fast.

This was the immediate fulfillment of Joel’s prophecy; however, there are multiple, deeper layers of this prophecy.  For example, Peter quotes portions of Joel (Joel 2:28, 29) as fulfilled in Acts 2:16-20 with the pouring out of God’s spirit at Pentecost upon the disciples. The Roman destruction of Jerusalem occurred about 36 years later (AD 70) because the religious leaders representing the nation had crucified our Lord (AD 33).    

In our Lord’s great prophecy of the end times, Jesus quotes from Joel 2:10 in Matthew 24:29. He referenced the sun being darkened and the moon not giving her light as signs of His invisible second advent. The repeated use in Joel of the phrase “the day of the Lord” points to the time at the end of the Christian age when there would be the ultimate fulfillment of Joel’s prophecies.    

In each of these prophetic fulfillments: the Assyrian invasion, Pentecost, destruction of Jerusalem, our Lord’s second presence, the prophecy of Joel is applied with ever increasing degrees of severity.  Each period involves the destruction of Israel, the punishment of the nations that come against Israel, and the reformation and blessing of the Jews. In the grand finale of this prophecy, Joel describes the permanent blessing of Israel and the world in Christ’s kingdom (Joel 3:17-21).

A parallel interpretation of Joel’s prophecy refers to the “spiritual” house of Israel, a term used to describe the Christian church. When the Apostles were present, the spiritual house of Israel was completely faithful. After they fell asleep, the church became contaminated and intoxicated with the spirit of the world (see Revelation 17:6). The Lord, therefore, pronounced judgment on them (similar to natural Israel) and will eventually destroy these babylonish churches (Revelation 14:8).  Still to come is the gathering of the nations to the valley of Jehoshaphat (Joel 3:2, 3:12) (also called Armageddon in Revelation 16:16). It is here that the final destruction of the world’s social, financial, political and false religious systems will occur. After the old order is demolished, Christ will establish God’s true kingdom on earth (Matthew 6:10). During this kingdom, repentance (as pictured in fasting by the Joel prophecy) will be required by all!

Additional Resources:
Christian Questions Podcast 
Episode #1333: “Should Christians Fast?”
The how, when and why of appropriate Christian fasting
Preview Video
CQ Rewind Show Notes

Episode #826: Why Focus on Fasting and Prayer?
The role of fasting (particularly) and praying in our lives
CQ Rewind Show Notes 

Blog post: Is drinking water allowed during a Christian fast?