Jamieson, Fausset and Brown on Matthew 7:15

15. Beware--But beware.

of false prophets--that is, of teachers coming as authorized expounders of the mind of God and guides to heaven. (See Ac 20:29, 30; 2Pe 2:1, 2).

which come to you in sheep's clothing--with a bland, gentle, plausible exterior; persuading you that the gate is not strait nor the way narrow, and that to teach so is illiberal and bigoted--precisely what the old prophets did (Eze 13:1-10, 22).

but inwardly they are ravening wolves--bent on devouring the flock for their own ends (2Co 11:2, 3, 13-15).