In religion, a false prophet or pseudoprophet is a person who falsely claims the gift of prophecy or divine inspiration, or to speak for God, or who makes such claims for evil ends. Often, someone who is considered a "true prophet" by some people is simultaneously considered a "false prophet" by others, even within the same religion as the "prophet" in question. In a wider sense, it is anyone who, without having it, claims a special connection to the deity and sets themself up as a source of spirituality, as an authority, preacher, or teacher. Analogously, the term is sometimes applied outside religion to describe someone who fervently promotes a theory that the speaker thinks is false.
Christian eschatology originated with the public life and preaching of Jesus. Throughout the New Testament and some of the early Christian apocryphal writings, Jesus warns his disciples and apostles multiple times of both false prophets and false Messiahs, and believers are frequently adjured to beware of them and stay vigilant.
In the Sermon on the Mount (Matthew 7:15–20), Jesus warns his followers of false prophets:
The canonical gospels address the same point of a false prophet predicting correctly, and Jesus predicted the future appearance of false Christs and false prophets, affirming that they can perform great signs and miracles, for example, in the Olivet Discourse given on the Mount of Olives:
In the Gospel of Luke, Jesus brought out an ethical application for his disciples using the analogy of false prophets in the Old Testament:
In the Book of Acts, the apostles Paul and Barnabas encountered a false prophet named Elymas Bar-Jesus on the island of Cyprus:
This particular story likewise best matches the model found in Deuteronomy. The claim here is that Elymas is trying to turn Sergius Paulus from the true faith, just like the false prophet described in the preceding verses. In these verses, we do not see Elymas prophesying as the term is popularly understood, so the model seems to fit this scenario best.
The Second Epistle of Peter makes a comparison between false teachers and false prophets and how the former will bring in false teachings, just like the false prophets of old:
The First Epistle of John warns those of the Christian faith to test every spirit because of these false prophets:
The most well-known New Testament false prophet is the one mentioned in the Book of Revelation. The False Prophet is ultimately cast into the fiery lake with burning sulphur:
And the Beast was captured, and with it the false prophet who in its presence had worked the signs by which he deceived those who had received the mark of the Beast and those who worshiped its image. These two were thrown alive into the lake of fire that burns with sulphur.
And the Devil who had deceived them was thrown into the lake of fire and sulphur, where the Beast and the false prophet were, and shall be tormented day and night forever and ever.
Another mention of a false prophet in the New Testament is the "antichrist spirit which denies the Son". In the New Testament, the word antichrist (Greek: antikhristos) appears mainly in the Johannine epistles and in the plural, denoting those who deny and/or don't believe in the messianship of Jesus. A similar term, pseudochrist (Greek: pseudokhristos, meaning "false messiah"), is used by Jesus in the Gospels. These terms seem to refer to a category of people rather than a single individual.
The Quran states that Muhammad is the "Seal of the Prophets" and Last and Final of the Prophets, which is understood by mainstream Sunni to mean that anyone who claims and recognised by people him as a new prophet or calls him a Prophet after him those all are false prophet. All mainstream Muslim scholars' perspectives from both Sunni and Shīʿa denominations don't consider the Second Coming of ʿĪsā (Jesus) as the coming of a new prophet, since the Islamic Messiah had already been an existing prophet and will rule by the Quran and sunnah of Muhammad, bringing no new revelation or prophecy.
Thawban ibn Kaidad narrated that Muhammad said:
"There will be 30 dajjals among my Ummah. Each one will claim that he is a prophet; but I am the last of the Prophets (Seal of the Prophets), and there will be no Prophet after me."
Abu Hurairah narrated that Muhammad said:
"The Hour will not be established (1) till two big groups fight each other whereupon there will be a great number of casualties on both sides and they will be following one and the same religious doctrine, (2) till about thirty Dajjals (liars) appear, and each one of them will claim that he is Allah's Messenger..."
Muhammad also stated that the last of these dajjals would be the Antichrist, Al-Masih ad-Dajjal (Arabic: دجّال, romanized: Al-Masīḥ ad-Dajjāl, lit. 'Deceitful Messiah'). The Dajjal is never mentioned in the Quran but he's mentioned and described in the ḥadīth literature. Like in Christianity, the Dajjal is said to emerge out in the east, although the specific location varies among the various sources. The Dajjal will imitate the miracles performed by ʿĪsā (Jesus), such as healing the sick and raising the dead, the latter done with the aid of demons (Shayāṭīn). He will deceive many people, such as weavers, magicians, half-castes, and children of prostitutes, but the majority of his followers will be Jews. According to the Islamic eschatological narrative, the events related to the final battle before the Day of Judgment will proceed in the following order:
11 Hadith also report on the “Greater Signs” of the end, which include the appearance of the Antichrist (Dajjal) and the reappearance of the prophet Jesus to join in battle with him at Dabbiq in Syria, as well as the arrival of the Mahdī, the “guided one.” As another hadith attributed to Alī ibn Abī Talib puts it, “Most of the Dajjal’s followers are Jews and children of fornication; the Dajjal will be killed in Syria, at a pass called the Pass of Afiq, after three hours are gone from the day, at the hand of Jesus".
Samra ibn Jundab reported that once Muhammad, while delivering a ceremonial speech at an occasion of a solar eclipse, said:
"Verily by Allah, the Last Hour will not come until 30 dajjals will appear and the final one will be the One-eyed False Messiah."
Anas ibn Malik narrated that Muhammad said:
There is never a prophet who has not warned the Ummah of that one-eyed liar; behold he is one-eyed and your Lord is not one-eyed. On his forehead are the letters k f. r. (Kafir).
Dajjal is blind of one eye and there is written between his eyes the word" Kafir". He then spelled the word as k. f. r., which every Muslim would be able to read.
Imam Mahdi (Arabic: ٱلْمَهْدِيّ, romanized: al-Mahdī, meaning "the rightly guided one") is the redeemer according to Islam. Just like the Dajjal, the Mahdi is never mentioned in the Quran but his description can be found in the ḥadīth literature; according to the Islamic eschatological narrative, he will appear on Earth before the Day of Judgment. At the time of the Second Coming of Christ, the prophet ʿĪsā shall return to defeat and kill al-Masih ad-Dajjal. Muslims believe that both ʿĪsā and the Mahdi will rid the world of wrongdoing, injustice, and tyranny, ensuring peace and tranquility. Eventually, the Dajjal will be killed by the Mahdi and ʿĪsā at the gate of Lud, who upon seeing Dajjal will cause him to slowly dissolve (like salt in water).
Jesus is rejected in every branch of Judaism as a failed Jewish Messiah claimant and a false prophet.
The Books of Kings records a story where, under duress from Ahab, the prophet Micaiah depicts God as requesting information from his heavenly counsel as to what he should do with a court of false prophets. This depiction is recorded in 1 Kings 22:19–23:
It is possible that Micaiah meant to depict the false prophets as a test from YHWH. It is also possible that it was meant as a slur on Ahab's prophets, such as Zedekiah, the son of Chenaanah.
The penalty for false prophecy, including speaking in the name of a god other than YHWH or speaking presumptuously in YHWH's name, is death (Deuteronomy 18:20). Likewise, if a prophet makes a prophecy in the name of YHWH that does not come to pass, that is another sign that he is not commissioned of YHWH and that the people need not fear the false prophet (Deuteronomy 18:22).
The Jewish Koine Greek term pseudoprophetes occurs in the Septuagint (Jeremiah 6:13, 33:8-11, 34:9, 36:1-8, Zechariah 13:2); Flavius Josephus (Antiquities of the Jews 8-13-1, 10-7-3, The Jewish War 6-5-2); and Philo of Alexandria (Specific Laws 3:8). Classical Pagan writers used the term pseudomantis.
The term false prophet is sometimes applied outside religious usage, to describe promoters of scientific, medical, or political theories which the author of the phrase thinks are false. Paul Offit's 2008 book Autism's False Prophets applied the phrase to promoters of unproven theories and therapies such as the unsupported relationship between thiomersal and vaccines and chelation therapy. Ronald Bailey's 1993 book Ecoscam: The False Prophets of Ecological Apocalypse applied the phrase to promoters of the global warming hypothesis; however, by 2005 Bailey had changed his mind, writing "Anyone still holding onto the idea that there is no global warming ought to hang it up."
General info from Wikipedia.org