The book of Joel admirably illustrates the intimate connection which subsisted for the prophetic mind between the sorrows and disasters of the present and the coming day of Jehovah: the one is the immediate harbinger of the other. In an unusually devastating plague of locusts, which, like an army of the Lord,[1] has stripped the land bare and brought misery alike upon city and country, man and beast--"for the beasts of the field look up sighing unto Thee," i. 20--the prophet sees the forerunner of such an impending day of Jehovah, bids the priests summon a solemn assembly, and calls upon the people to fast and mourn and turn in penitence to God. Their penitence is met by the divine pity and rewarded by the promise not only of material restoration but of an outpouring of the spirit upon all Judah,[2] which is to be accompanied by marvellous signs in the natural world. The restoration of Judah has as its correlative the destruction of Judah's enemies, who are represented as gathered together in the valley of Jehoshaphat--i.e. the valley where "Jehovah judges"--and there the divine judgment is to be executed upon them. [Footnote 1: Some regard the locusts as an allegorical designation for an invading army. But without reason: in ii. 7 they are _compared_ to warriors, and the effect of their devastations is described in terms inapplicable to an army.] [Footnote 2: The sequel, in which the nations are the objects of divine wrath, shows that the "all flesh," ii. 28, must be confined to Judah.] The theological value of the book of Joel lies chiefly in its clear contribution to the conception of the day of Jehovah. As Marti says, "The book does not present one side of the picture only, but combines all the chief traits of the eschatological hope in an instructive compendium"--the effusion of the spirit, the salvation of Jerusalem, the judgment of the heathen, the fruitfulness of the land, the permanent abode of Jehovah upon Zion. These features of the Messianic hope are, in the main, characteristic of post-exilic prophecy; and now, with very great unanimity, the book is assigned, in spite of its position near the beginning of the minor prophets, to post-exilic times.