"And many false prophets shall rise, and shall deceive many." (Matthew 24:11)
In the apostolic period, two main gifts of the Spirit were those of the apostle and prophet. In fact, the church itself was "built upon the foundation of the apostles and prophets" (Ephesians 2:20). One function of these men was to receive and transmit God's revelation to His people--first verbally, then eventually written in permanent form in the New Testament. "Which in other ages was not made known unto the sons of men, as it is now revealed unto his holy apostles and prophets by the Spirit" (Ephesians 3:5).
The apostle Paul revealed also that such prophecies would cease once they were no longer needed. "When that which is perfect |or 'complete'| is come, then that which is in part shall be done away" (1 Corinthians 13:9-10). Clearly in the context, this refers to the complete revelation of God. When the last book of the Bible was transmitted to the church by the last living apostle, the Lord warned us neither to "add unto" nor to "take away from the words of the book of this prophecy" (Revelation 22:18-19).
But many false prophets have indeed "gone out into the world" (1 John 4:1), just as Jesus warned, and they have "deceived many." One of them, a self-asserted seventh century "prophet" from Arabia, received certain "revelations" from a "god" that were vastly different from those of the God of the Bible, and his followers now number over a billion.
There have been others, before and since, and the Lord Jesus warned us always to "beware of false prophets" (Matthew 7:15). The basic criterion by which to test any alleged prophecy, ancient or modern, is whether or not it fully conforms to the written Word of God, the Bible. "To the law and to the testimony: if they speak not according to this word, it is because there is no light in them" (Isaiah 8:20). HMM