Yeshua warned His disciples against false prophets. He said, “Beware of the false prophets, who come to you in sheep's clothing, but inwardly are ravenous wolves” (Matthew 7:15). The Torah addresses the problem of false prophets by establishing careful criteria for authentication. According to the Torah, a failed prediction disqualifies a would-be prophet: “If the thing does not come about or come true, that is the thing which the LORD has not spoken” (Deuteronomy 18:22). He is a false prophet and liable to the death penalty: “That prophet shall die” (Deuteronomy 18:20). Even if the prediction does come about and even if the prophet offers signs, wonders, and miracles, he still might not be a true prophet. If he entices Israel into idolatry or to turn away from the commandments of the Torah, he is a false prophet, despite all his miraculous proofs (Deuteronomy 13:4-5).
False prophets were active in the first century, but when Yeshua warned his disciples against false prophets, He used the term broadly to refer to anyone claiming to be a spiritual leader among the believers—not just prophets. Though they disguise themselves as genuine followers of the Master, they “inwardly are ravenous wolves” (Matthew 7:15). While claiming to define God’s will for others, they do not conduct themselves according to the Torah.
The chief criterion by which the false prophet may be recognized is not necessarily theological or miraculous. Yeshua told His disciples to watch the fruit of their lives. In rabbinic literature and apostolic teaching, a man’s “fruits” are his deeds. Good fruits are good deeds; bad fruits are acts of wickedness.
Yeshua compared people to trees, as it says in the Torah, “The man is the tree of the field” (Deuteronomy 20:19). Good trees bear good fruits; bad trees do not. “Each tree is known by its own fruit. For men do not gather figs from thorns, nor do they pick grapes from a briar bush” (Luke 6:44). Yeshua warned, “Every tree that does not bear good fruit is cut down and thrown into the fire” (Matthew 7:19). While we should not pass judgment on our brothers, we are to exercise discernment. Yeshua told us that we will recognize those who are genuine by their deeds. We are not to look for miracles or spiritual fireworks.