That the battle's outcome is a foregone conclusion is clear from the two scenes that follow (each introduced by I saw, vv. 17, 19). John sees first an angel standing in the sun (and therefore beyond the sky), inviting all the birds in the sky to come, gather together for the great supper of God, so that you may eat the flesh of kings, generals, and mighty men, of horses and their riders, and the flesh of all people, free and slave, small and great (v. 18). This is the ghastly counterpart to the joyful "wedding supper of the Lamb" (v. 9). It anticipates the end of battle, when the ground is strewn with corpses, and the birds of prey claim their due. Already it is clear that the corpses are not those of the armies accompanying the rider on the white horse, but the armies arrayed against him. If the rider on the white horse evoked for John and his readers the traditional expectation of Jesus' return to earth as Son of Man, it is natural to wonder if perhaps this scene is intended to echo in some way the strange saying of Jesus in that connection, "Wherever there is a carcass, there the vultures will gather" (Mt 24:28; compare Lk 17:37).
Together the visions of the birds of prey in the sky (vv. 17-18) and the outcome of the so-called battle (vv. 19-21) form a kind of chiasm, that is, the same three elements are repeated in reverse order:
(a) the birds of the sky are invited to feast (v. 17)
(b) the doomed armies are described (v. 18)
(c) the beast gathers these armies for battle (v. 19)
(c') the beast and false prophet are captured and thrown into the lake of fire (v. 20)
(b') the armies are killed by the sword of the rider on the white horse (v. 21)
(a') the birds feast on their flesh (v. 21) The effect of the chiasm is to dramatize the inevitability of the outcome. The armies arrayed against the rider on the white horse are slaughtered by the sword that came out of the mouth of the rider on the horse, that is, "the Word of God." God speaks and it is done. The angel standing in the sun (v. 17) knows the end from the beginning. The beast has not been heard from since chapter 17, where his involvement in the conflict was made unmistakably clear (17:13-14). The false prophet, mentioned only once before in passing without further identification (16:13), is here explicitly said to be the one who had performed the miraculous signs on the beast's behalf and had deluded those who had received the mark of the beast and worshiped his image (v. 20). This identifies him as the second beast "coming out of the earth" who had enforced on the earth's inhabitants the worship of the beast from the sea (13:11-17). The false prophet played no role in the vision or the explanation by the angel in chapter 17, yet the two beasts are to John inseparable, and they go to their destruction together in this their final scene.
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