Matthew 7:15

Beware of false prophets, who come to you in sheep's clothing, but inwardly are ravening wolves. By their fruits ye shall know them.

This warning naturally flows out of what Jesus had just said. The broad way will have its advocates, false teachers, who will attempt to widen the narrow way and breach the strait gate. This passage suggests the great apostasy which is elaborated in the following New Testament passages: Acts 20:29-31; 2 Corinthians 11:1-3; 2 Thessalonians 2:1-12; 1 Timothy 4:1-5; 2 Timothy 3:1-8; 4:1-5; 2 Peter 2:1-3; 3:1-7; and Revelation 17 and Revelation 18. It is essential that Christians recognize false teachers or prophets, as they are called here.

By their fruits ye shall know them. To be effective in deceiving God's people, it is essential that false teachers be disguised, hence the "sheep's clothing." This means that the church itself shall be the theater of operations for these destructive teachers. They will appear as ministers, officers, and advocates of religion. The one sure test is their fruits. That which sows discord, divides, debilitates, hinders, or thwarts in any way the true spiritual family of God is to be rejected. The great test is the false teacher's attitude toward Christ. Those who question his authority or go beyond his word are clearly of the evil one. The only proper way in which this admonition can be heeded is for the Lord's sheep to know the Shepherd's voice, that is, they must know his word and doctrine. The remainder of the Sermon on the Mount is devoted to those things which will enable the child of God to distinguish between true and false teachers of religion.