Beware of false prophets, who come to you in sheep's clothing, but inwardly they are ravening wolves.
All Commentaries on Matthew 7:15 Go To Matthew 7
Augustine of Hippo
AD 430
Here, therefore, those who promise a wisdom and a knowledge of the truth which they do not possess, are especially to be guarded against; as, for instance, heretics, who frequently commend themselves on account of their fewness. And hence, when He had said that there are few who find the strait gate and the narrow way, lest they [the heretics] should falsely substitute themselves under the pretext of their fewness.