Joel is commanding the leaders to call for a fast which is a sacred assembly, a gathering designed for prayer and repentance, for crying out to God for His mercy. Joel presents a vivid picture of the consequences of sin and shows us how to respond with true repentance. The kind of repentance that leads to holiness is not merely an outward show, but an inward, sincere, heartrending brokenness over sin. When sin occurs corporately, as it did in Israel, God calls upon leaders to gather the people in a solemn assembly in which they fast, pray, and cry out for His mercy and forgiveness. As we see sin in the church and in the nation, we would do well to heed Joel’s exhortations and cry out to God corporately for our generation. Fasting and prayer are meant to seek God’s answer for difficult situations.