2 Peter 2:1-3

1 But there were also false prophets among the people, even as there will be false teachers among you, who will secretly bring in destructive heresies, even denying the Lord who bought them, and bring on themselves swift destruction.

² And many will follow their destructive ways, because of whom the way of truth will be blasphemed.

³ By covetousness they will exploit you with deceptive words; for a long time their judgment has not been idle, and their destruction does not slumber.

the people (v.1) – The Old Testament Israelites (Deuteronomy 13:1-5; 1 Kings 13:18, 22:5-23; Jeremiah 5:13, 31; 6:13, etc.)

false teachers (v.1) — The falsity may refer to the content of their teaching or to their claim to be teachers. Probably both are implied — Guthrie, page 1254.

heresies (v.1) = literally, chosen beliefs. In Scripture, it refers to wrong beliefs deliberately chosen by man (as opposed to true beliefs revealed by God).

Having established that prophecy came through holy men who were moved by the Spirit in time past [2 Peter 1:20-21], Peter reminds his hearers that there were also false prophets among the people of Israel (Deuteronomy 13:1-5). Then he adds, “even as there shall be false teachers among you,” that is, their counterparts. They were not to think that they were exempt from these insidious attacks, nor should we. …

A false teacher is someone who knowingly, deceitfully, and deliberately teaches that which is untrue. We normally associate false teachers with the unregenerate; however, this is not always the case. Paul wrote to the Galatians regarding his defense of the gospel of the grace of God at Jerusalem: “and that because of false brethren unawares brought in, who came in privily to spy out our liberty which we have in Christ Jesus, that they might bring us into bondage: To whom we gave place by subjection, no, not for an hour; that the truth of the gospel might continue with you” (Galatians 2:4-5). — Sadler, pages 196-197

destructive (v.2) = licentious, wanton, outrageous, shocking to public decency, lewd

The false teachers of the day [Gnostics] tended to argue that it did not matter how the Christian behaved, as grace could forgive every sin. — Guthrie, page 1254.

The false teaching led to licentiousness, but it was disguised as truth. As a result, unbelievers didn’t distinguish between the false and the true and reviled the true.

The unregenerate false teachers spoken of here are the masters of deception. Peter effectively warned his countrymen to beware of those who, after his death, would lie in wait to deceive. They are wolves in sheep’s clothing. It is important to note that these deceivers “bring in damnable [destructive] heresies, even denying the Lord that bought them.” They deliberately bring falsehood alongside the truth that they might deceive the unsuspecting. This is often accomplished by introducing something new as a fuller expression of sound doctrine. …

These false teachers denied the very One who provided redemption for them. While they probably taught their hearers that Christ was a great prophet and teacher, they rejected the truth that He was the Redeemer of Israel. These “wells without water” blatantly denied Christ’s subsitutionary death, precious shed blood, and bodily resurrection. They even called into question the inspiration of the Scriptures themselves when they defiantly declared “Where is the promise of His coming?” (2 Peter 3:4). the trademark of all false teachers is the denial of the Deity of Christ. …

How do these workers of iniquity so effectively mislead their followers? As Peter says, many shall follow” them. Since the natural man is inherently religious and would rather believe a lie, he’s easy prey for the “pernicious ways” and “feigned words” of a false teacher. Notice they are identified by their pernicious ways. In other words, they’re outrageous, shameless, and given to excess. These unscrupulous preachers have magnetic personalities that draw men to them. And with “feigned words” or persuasive speech … they lead men to destruction. …

The goal of these false teachers is to exploit their unwary followers. They are solely out for financial gain; therefore, Peter warns those that are intrigued by their notoriety accordingly, they will “make merchandise of you.” Like a thief, they will rob you blind, while promising you health, wealth, and prosperity. — Sadler, pages 198-199.

exploit (v.3) = make a gain or business of

their judgment has not been idle, and their destruction does not slumber (v.3) — Not … idle means that judgment is impending (hard on their heels). Asleep is a vivid metaphor (waits for them with unsleeping eyes) Retribution is certain, though it may not be swift, for the man who leads another astray. — Guthrie, page 1254.

Verse 1 says that the false teachers bring on themselves “swift judgment.” Verse 3 (see Guthrie’s comment above) seems to be saying that it may not be immediate. I think this is a case where you have to remember the context of Peter’s letter. For those in the first century, it may have seemed that the false teachers were getting away with their heresies (although Peter made it clear that their judgment was coming. For those in the Tribulation, the false will be judge very quickly.

I’m not sure I entirely agree with Sadler that false teachers always know they’re wrong. There are prominent “Christian” pastors today who are leading masses of people astray, but I have to think some of them “believe” they’re right. And what about those Paul referred to in Galatians 2:4-5? Did they know they were wrong? In a sense, coming from James, they were right for kingdom Jews, but wrong for Gentiles. Because they acted in secret, they obviously knew Paul was teaching something different, but did they know they were wrong? I don’t know.

Maybe false teaching isn’t only deliberate falsehood, but falsehood brought about by wrong motives—a desire for wealth, concern for one’s reputation, a longing to become popular. There are many prominent speakers who have taken a stand and built huge ministries based on bad doctrine. To recant would be to lose all their standing, power, and wealth. But again, keep in mind that Peter’s audience was facing/will face specific threats.