The first factor added here is that God recognizes that false prophets, through the power of Satan, can accomplish signs and wonders. The magicians of Egypt imitate Moses' staff-into-a-serpent miracle before Pharaoh (Exodus 7:8-12). The end-time False Prophet will do similar signs as the Two Witnesses, causing most of the world's population to worship the Beast (Revelation 13:11-15). Paul warns in II Corinthians 11:13-15 that Satan's servants are clever counterfeits of Christ's. Signs, wonders, and miracles, then, are not conclusive proof that a prophet is from God.
The second factor Deuteronomy 13 adds is our need to recognize the spiritual message accompanying the prophet's signs and predictions. This is the essence of the apostle John's admonition, "Beloved, do not believe every spirit, but test the spirits, whether they are of God; because many false prophets have gone out into the world" (I John 4:1). No matter how impressive or accurate a prophet's miracles or prophecies, his credibility hangs on whether he leads people toward or away from God.
The following questions, then, must all be answered before we judge a person as a true or false prophet:
1. Does he claim to prophesy in God's name or in a false god's name?
2. Do his prophecies come to pass?
3. Does he do signs and wonders?
4. Does he teach the truth based on God's Word?
Richard T. Ritenbaugh
Was Herbert Armstrong a False Prophet?