The prophet Joel ("Jehovah is God") is distinguished from other men bearing this rather common name by the statement that he was the son of Bethuel. Nothing definite is known concerning the circumstances of his life. Nor can we tell with certainty where he lived, although it seems most probable that he labored in Judea and proclaimed his prophecies in Jerusalem. Joel belongs to the earliest of the so-called minor prophets, for there are evident references to his book in the writings of Amos and even of Isaiah. The fact that he names the Phoenicians, Philistines, Egyptians, and Edomites as the enemies of Judah, but neglects to mention the Syrians, indicates that this world-power and others were not yet a factor when he lived. Altogether, it seems best to assume that Joel lived in the earlier half of the ninth century before Christ.
The Book of Joel was occasioned by a terrible visitation of grasshoppers and drought, which he explains as the precursors and signs of the last Great Judgment of Jehovah, which may be averted only by a sincere repentance. The book is clearly divisible into two parts. The first part is a heartrending lament over the affliction of the people on account of the plague of locusts, together with an urgent call to repentance, 1:1-2:17. The second part is a promise of divine mercy for all those who repent, first concerning temporal blessings in the near future, then also regarding spiritual, Messianic benefits, particularly the outpouring of the Spirit, as the last great deed of God before the coming of the terrible Day of the Lord.
The language of the prophet excels in classical beauty and purity, and some of his passages are without a parallel for force of expression. The blessings of the Messianic age are brought out in periods of surpassing splendor and power. The salient points of the book are named by Peter in his great sermon on Pentecost, Act_2:16-21, and by Paul, Rom_10:13.