15 "Beware of false prophets who come disguised as harmless sheep but are really vicious wolves. 16 You can identify them by their fruit, that is, by the way they act. Can you pick grapes from thornbushes, or figs from thistles? 17 A good tree produces good fruit, and a bad tree produces bad fruit. 18 A good tree can't produce bad fruit, and a bad tree can't produce good fruit.
Matthew Henry's Commentary on Matthew 7:15-18
Commentary on Matthew 7:15-20
(Read Matthew 7:15-20)
Nothing so much prevents men from entering the strait gate, and becoming true followers of Christ, as the carnal, soothing, flattering doctrines of those who oppose the truth. They may be known by the drift and effects of their doctrines. Some part of their temper and conduct is contrary to the mind of Christ. Those opinions come not from God that lead to sin.