The False Prophet is the second beast which John sees which comes up out of the earth [#3-#18] having two horns like a lamb and who spoke like a dragon (Rev. Rev. 13:11+). His appearance is benign, like that of a lamb, but his prophecies and commands have their source in the devil. This is why Scripture refers to him as the False Prophet (Rev. Rev. 19:20+; Rev. 20:10+). The False Prophet performs great signs and miracles which are used to witness to the Beast from which he derives his power. He exercises all the authority of the first beast in his presence and causes the earth and those who dwell in it to worship the first beast [#16-#18] (Rev. Rev. 13:12+). He causes those on the earth to worship the Beast and to make an image to the beast [#18-#19] (Rev. Rev. 13:14+). He is even granted power to give breath to the image of the beast (Rev. Rev. 13:15+). It appears that the miracles he performs are genuine, but what they attest to is false. It is the False Prophet who causes all men to receive a mark in order to be able to buy or sell (Rev. Rev. 13:16-17+). Along with the dragon and the Beast, he forms an antitrinity wherein the dragon occupies a position like that of the Father, the Beast like that of the Son, and the False Prophet like that of the Holy Spirit, but testifies to the false son . All three are the source of demons which gather the kings of the earth to battle (Rev. Rev. 16:13-14+). (See Campaign of Armageddon.) Both the False Prophet and the Beast are taken at the Second Coming of Christ and cast into the Lake of Fire as its first populace (Rev. Rev. 19:20+). They are still there one thousand years later when joined by the devil (Rev. Rev. 20:10+).1 No doubt the False Prophet plays a key role in the deception which Paul described in his letter to the church at Thessalonica:
The coming of the lawless one is according to the working of Satan, with all power, signs, and lying wonders, and with all unrighteous deception among those who perish, because they did not receive the love of the truth, that they might be saved. And for this reason God will send them strong delusion, that they should believe the lie, that they all may be condemned who did not believe the truth but had pleasure in unrighteousness. (2Th. 2Th. 2:9-12) [emphasis added]
He is an instrument of both the dragon and the Beast, but ultimately of God. See Symbols of Kingdoms. See commentary on Revelation 13:11.
1 Their continued existence in the lake one thousand years later provides irrefutable evidence against annihilationism. Those whose destiny is the Lake of Fire are not consumed, but continue to suffer forever.