I. Author, Date, Purpose
Nothing is known of the prophet Joel except that which is told or may be inferred from the book that bears his name. He is identified as the son of Pethuel (1:1). Perhaps because of its similarity to Bethuel (Ge 22:22-23), the Septuagint has Bethuel as the father's name. The name Joel, meaning “Yahweh is God,” is borne by sixteen other men in the OT. However, some of these may be duplications (Brettler, 494-95). Since Joel's prophecy is concerned only with Judah and speaks familiarly about Jerusalem, it is assumed that he was a resident of Judah.
To date this book we are completely dependent on internal evidence. Little is offered. In ch. 3 Joel mentions such places or people as Tyre, Sidon, Philistia, the Greeks, the Sabeans, Egypt, and Edom. About such nations as Syria, Assyria, and Babylonia, which are of such importance in other prophetic books, he is silent. Neither does he allude to the northern kingdom. Joel is concerned about the proper maintenance of temple services, but he does not cry out against specific sins of the people. There is silence with regard to the king, but the priests are prominent (Driver, 12).
From this and similar data a date near 400 b.c. is generally accepted, although dates ranging from the middle of the ninth century b.c. to 350 b.c. are sometimes proposed.
The occasion of this book was an awesome invasion of locusts followed by severe drought which threatened the very existence of life. Joel sees in these natural calamities evidence of God's judgment on his people and a symbol of the impending final Day of the Lord. Joel claims that the source of his message is the Lord himself (1:1).