A great locust plague devastated Judah in Joel's day — 'what the cutting locust left, the swarming locust has eaten; and what the swarming locust left, the hopping locust has eaten' (Joel 1:4). Joel called the priests and the people to repentance and fasting in sackcloth.
After the call to repentance came the great promise: '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, and your young men shall see visions. Even upon the menservants and maidservants in those days, I will pour out my Spirit' (Joel 2:28–29). Peter cited the prophecy in his first sermon at Pentecost (Acts 2:17–21) as fulfilled in the very descent of the Holy Spirit on the apostles. Joel's words are read by the Church each year at the Easter Vigil among the Old Testament prophecies of the New Covenant.