In Matthew 7:15 Jesus says, "Watch out for false prophets."
This is a remarkable statement particularly when viewed against the backdrop of postmodernity. It indicates that Jesus actually believed there was such a "thing" as a "false prophet." This is radical today. Radical because there are many people who believe that it is the height of bigotry and insensitivity to suggest that anybody is wrong. Today, it is all a matter of perspective. No one knows everything and therefore in the end everyone is basically saying the same thing and heading in the same direction. There is no right and wrong, truth and error; just varying shades of grey. Interestingly enough, Jesus did not think that way. He warned his disciples about people who teach what is false, because he knows better than anyone else the dangers of such instruction.
Undergirding what Jesus says in this verse is the bedrock of objective truth. The idea that there is such a thing as "real truth" that is true for everyone, everywhere, at all times, whether anyone believes it or not. This is something that historical Christianity has always affirmed based on the existence of God. Christians do not believe in just any kind of god; we believe in the eternal, self-existent Creator who is independent of all that he has made and yet intimately involved with it at the same time. This God is truth in and of himself and he defines what is true for us as well. Consequently, we are not left to float on a sea of subjectivity that has no bottom or shore, we can know the truth and walk in it by God's grace and mercy.
Not only does Jesus believe in objective truth, but he believes that truth matters. In the end there is a very real sense in which our salvation depends on whether we know, love, believe and obey the truth as it is made known in Jesus Christ. Previous generations of Christians seemed to understand this better than many today. They fought and were willing to lay down their lives to defend the gospel from corruption. They did not feel the modern need to be innovators. They understood that truth, by its very nature, has a certain "fixity" to it and should not be tampered with. Our task is to rightly understand what God is saying and then carefully apply it to the world in which we live.
According to Jesus, Christians are responsible to watch out for false prophets. It is not merely the responsibility of church leaders and scholars, it is everyone's responsibility. We cannot hide, or shut our eyes, or stick our heads in the sand. We must not fall prey to a false kind of humility which acts as though it is too simple to discern right from wrong. Sometimes this is also joined to a false kind of submission that does not think for iself but surrenders to the so-called "experts" or "public opinion." If we are deceived it is our own fault. We do not have to fall into the false prophet's trap. In the verses that follow (Matthew 7:16-20) Jesus tells us a number of things that will help us escape this spiritual snare.
First, we must recognize that false prophets have always been a problem for the people of God. In the Old Testament, God warned the children of Israel about those who spoke out of their own imaginations, claiming to have a message from God, when they did not. In the Gospels, Jesus warned about the Pharisees and teachers of the law who made their converts twice as much sons of hell as they themselves were (Mt.23:15). In Matthew 24:11 he warned that many false prophets would appear during the gospel age and would deceive many. In other passages, the apostles Paul and Peter also warn churches of this kind of trouble (cf. Acts 20:28-31; 2 Peter 2:1-22). What was true in the past continues to be true today. To be forewarned is to be forearmed.
Second, false prophets are often notoriously difficult to recognize. This is not always the case. Some are so obviously false that only the most obtuse are taken in. But many others are like ferocious wolves in sheep's clothing. These are much more difficult to detect because they pick their words carefully and do not live outrageous lives. They are often decent, pleasant people, but it is only a cover what what is really going on inside. They are like computer viruses which go undetected until it is too late and they have done their damage. They are difficult to detect because of their relationship to the prince of darkness who knows how to masquerage as an angel of light when it suits his diabolical purposes (2 Corinthians 11:13-15).
Third, protecting ourselves involves asking some serious questions about 1) what is being taught, 2) the life of the teacher and 3) the influence of their teaching on others. Jesus speaks about all these things by making use of a metaphor that involves trees and their fruit. Trees and bushes can look alike from the distance but an examination of their fruit will confirm their true identity. If we apply what Jesus is saying to a teacher's instruction we understand that anyone who does not acknowledge his words is a false prophet. Anyone who claims to be superior to him or to have a revelation that goes beyond his, is a false prophet. Anyone who denies the "narrowness" of the gospel way is a false prophet. Anyone who tells people that they are going to heaven when they have never turned from their sins and put their faith in Jesus, and in him alone for salvation, is a false prophet.
If we apply what Jesus is saying to a teacher's way of life we should expect to find a relationship between what is being taught and they quality of the teacher's life. Truth should produce more and more humility, purity, prayerfulness and obedience to all that the Scriptures command. Where these things are absent something is wrong. One by-product of being made in the image of God is consistency. As time goes on it is increasingly difficult for human beings to teach one thing and do the opposite. It is hard for us to live with that kind of dissonance. We seek integration and authenticity and this tends to push us in the direction of consistency one way or another. If we are studying and proclaiming the truth by God's grace it should produce righteousness of life. If we are studying and proclaiming that which is false it will tend to have determinal affect on our behavior. The fruitfulness of our lives, or the lack of it, will give us away to those who look closely and are not blinded by the shimmer of success, personal charisma, or the opinion of others who may be equally deluded.
If we apply what Jesus is saying to a teacher's influence on others then we should look to see what is happening in the lives of those who are under his influence. Godless chatter makes people more and more ungodly (2 Timothy 2:16). False teaching can destroy the faith of some and lead them into a spiritual wasteland (2 Timothy 2:18). Paul tells us that divisiveness of one of the tragic results of error (2 Timothy 2:23; Titus 1:11; 3:9). Whereas truth proclaimed in love produces more love, righteousness, maturity and a growing desire to serve God (1 Timothy 1:4-7; 2 Timothy 3:16-17; Titus 1:1).
Jesus concludes his warning about false prophets by assuring us that every tree that does not bear good fruit is cut down and thrown into the fire. Truth is not to be trifled with but humbly received and obeyed. In a day like ours disciples of Jesus need to make sure that they are staying close to their Master. In his presence there is both safety and power.