The Day of the Lord is one of Scripture's most versatile prophetic concepts, appearing over 20 times across the Old and New Testaments. The prophets used it for both near-term events — Joel described a devastating locust plague as a foretaste of the Day (Joel 1-2), and Isaiah applied it to Babylon's fall (Isaiah 13:6-9) — and the ultimate future judgment. Amos shocked his audience by warning that they should not desire the Day of the Lord, 'for it is darkness, and not light' (Amos 5:18), overturning the popular assumption that God's intervention would only bring blessing for Israel. In the New Testament, Paul used the image of a 'thief in the night' (1 Thessalonians 5:2) to describe its sudden, unexpected arrival, while Peter described cosmic dissolution and renewal on that Day (2 Peter 3:10-13). What unifies every usage is God's direct intervention — a moment when the normal course of history is interrupted by divine action that simultaneously judges evil and delivers the faithful.