Joel 2:3

"A fire devoureth before them; and behind them a flame burneth: the land is as the garden of Eden before them, and behind them a desolate wilderness; yea, and none hath escaped them.

"None hath escaped them ..." This is the key that unlocks the extended meaning of the locusts in this passage. The locusts never hurt people; and clearly the disaster threatened here is against the population itself. The probability of this view being correct is greatly enhanced by the dual presentation of the locusts in Revelation 9. In phase I, there was no loss of human life; but in phase II, the "locusts" became a murdering army of 200,000,000 with a commission to destroy a third of the human race! The genius of the inspired writers in discerning these two phases in the life-cycle of the actual locust is certainly reflected in both Joel and the Book of Revelation. This two-phase phenomenon in the life of the locust was not known to the scientific community for generations; because it was not until 1921 that, "The centuries-old question posed by a locust swarm was answered (in 1921) by Sir Boris Uvarov."[10] The revelation of this "Secret of the Locust" was elaborately discussed by Robert A.M. Conley in 1969 thus:

"He discovered that one of the familiar green grasshoppers of the African and Asian bush is really the ravenous locust in another guise. When repeated rains dampen desert sands, thousands of eggs hatch. The hoppers constantly touch one another, triggering a change of behavior and color; they seek each other's company and turn yellow, black, and red."[11]

Quite evidently the peculiar use of the locust as a "type" by both Joel and the apostle John resulted from their inspiration in knowing what would remain unknown about the locusts until long millenniums afterward! The connection that this portion of the Bible has with the Book of Revelation is further pointed up by the mention here of the garden of Eden, that being the place where human rebellion against God began, where the sentence of death was imposed (and never repealed), and where God uttered his curse upon the ground "for Adam's sake." That ancient paradise (Eden) is also repeatedly mentioned in Revelation, and for exactly the same reasons as here. This reference by the prophet to the garden of Eden is laden with great significance.

"Fire devoureth before them, and behind them a desolate wilderness..." There is no need whatever to see this as any kind of metaphor. An invading army always burns everything in its path, leaving nothing behind except desolation.