The False Teachers, Their Message And Its Consequences (2 Peter 2:1-3).
The future tense here is probably intended simply to be a general future. The point is that the false teachers are at present among them and will continue on into the future. There will always be false teachers as Jesus had constantly warned.
1 But there were false prophets also among the people, even as there shall be false teachers among you, who privily shall bring in damnable heresies, even denying the Lord that bought them, and bring upon themselves swift destruction.
2 And many shall follow their pernicious ways;a by reason of whom the way of truth shall be evil spoken of.
3 And through covetousness shall they with feigned words make merchandise of you: whose judgment now of a long time lingereth not, and their damnation slumbereth not.