As Paul's analysis of the situation continues, he uses language that expresses regret and irony to describe these disguised "wolves." There is more to false teachers than false doctrine.
First, they have lost their spiritual bearings. They have wandered (v. 6)--an image of slow but steady movement away from some point. Perhaps in the beginning these teachers only drifted aimlessly. But as they hardened in their disbelief and became argumentative in their attempts to convince others of their views, their lives came to be characterized not by love but by controversy, impure hearts and ineffective consciences. They have wandered from the faith.
Second, they speak and teach foolishness (v. 6). Having left the faith and diverged from the standard of approved teaching, their doctrines and discussions are meaningless talk, devoid of truth (6:4-5). In choosing the word he does, Paul places their doctrine into the category of idolatry and paganism (compare Acts 14:15; 1 Pet 1:18).
Third, verse 7 reveals that they claim authority for their teaching. Teachers of the law, a title given to the rabbis (Lk 5:17; Acts 5:34), were regarded as the authoritative interpreters of Scripture. These enthusiasts were not interested in simply offering their ideas for consideration. Rather, they "taught" them as God's message and expected them to be received.
Finally, Paul's description of their "confidence" implies in this context stubbornness, a refusal to be denied. We might say they are dogmatic, which (along with the claim to authority) Paul regards with irony, since they have no real understanding of the matters they teach. Error, the claim to authority and dogmatic insecurity make a deadly combination to be sure, especially if these heretics began from positions of leadership in the church, as may well have been the case.
These characteristics make a timeless portrait of the false teacher. Doctrinal subtleties, special interpretation, spurious claims to authority, controversy and dogmatism ought to make God's people suspicious. At the same time, evidence of these same tendencies in our own lives ought to cause alarms to go off. From the human perspective, it is often a deeply rooted, though sometimes well-concealed, insecurity that drives one to take the lead in a heretical movement. We would do well to ask ourselves whether stubborn dogmatism that takes us beyond discussion to argument and anger is not motivated by such a fear. No rigid doctrinal structure can dispel this fear. An awareness of God's permanent love for us is integral to the solution, though there may be other elements that only skilled counseling can help us address. Then, while a desire to learn the deep truths of God's Word is commendable, if this leads us to embrace arcane views that run counter to the main lines of biblical teaching, we are headed for trouble. The remedy is not to stop thinking, for there is much yet to be discovered. However, theological investigation must be done in dialogue with the church. The individual needs the balance and testing that discussion with other mature believers will provide.