'Wolves' in the Bible

"Beware of false prophets, who come to you in sheep's clothing, but inwardly are ravening wolves.

"Behold, I send you out as sheep in the midst of wolves. Therefore be wise as serpents, and harmless as doves.

Go your ways. Behold, I send you out as lambs among wolves.

For I know that after my departure, vicious wolves will enter in among you, not sparing the flock.