Joel 1:15

The locust plague had destroyed (Heb. shadad) the fields and fruits of Judah, but Joel announced that things would get worse. Another day of destruction (Heb. shod) would come from the Lord, the Almighty (Heb. shadday). A locust plague was not only an evidence of God’s judgment (cf. Deuteronomy 28), but it had been a harbinger of future worse destruction in the past. A locust plague had preceded the plagues of darkness and death in Egypt (cf. Exodus 10-11). Thus, rather than seeing the locust plague as the end of the people’s troubles, Joel saw it as a prelude to something worse.

The day of the Lord is a term that appears frequently in the Old Testament, especially in the Prophets. It refers to a day in which the Lord is working obviously, in contrast to other days, the day of man, in which man works without any apparent divine intervention. Specifically, it is a day in which the Lord intervenes to judge His enemies. Gerhard von Rad argued that this term was originally associated with the Israelite concept of holy war, [Note: Gerhard von Rad, "The Origin of the Concept of the Day of the Lord," Journal of Semitic Studies 4 (1959):97-108.] but other scholars have disputed this aetiology. Most agree, however, that it had early associations with battles and conquest. Here the day of the Lord is obviously one of destruction, though elsewhere it also refers to a day of blessing. The eschatological day of the Lord that the prophets anticipated includes both judgment (in the Tribulation) and blessing (in the Millennium and beyond). Here Joel spoke of an imminent day of the Lord; it was coming on Judah relatively soon (cf. Isaiah 13:6; Ezekiel 30:2-3; Amos 5:18-20; Zephaniah 1:7-13).