As we will see in the chapter on Jude, the second chapter of 2 Peter has a good deal of the same content as Jude does, and they both cover that material in pretty much the same order. For this reason, experts on these letters believe there is some relationship between 2 Peter 2 and Jude. The three basic options are 1) 2 Peter drew on Jude, 2) Jude drew on 2 Peter, or 3) they both drew on a common source. 
One difference that we will see between 2 Peter 2 and Jude is that 2 Peter's descriptions of future false prophets seem less concrete than Jude's. Jude seems to be talking about a specific, concrete group of people that existed in his day, while 2 Peter 2 speaks much more generally about the false teachers of the future. Also, the false teachers of 2 Peter 2 are not obviously the same scoffers of 2 Peter 3 who question why Jesus hasn't returned yet.
So Peter begins his second chapter with a reminder that, along with true prophets in the early church, there were also false prophets as well (2:1). So Christians should always expect to have false teachers around. Peter then gives a series of illustrations to show that, while it may not be today, God will in the end both rescue the righteous and punish the wicked (2:9). He starts with fallen angels (2:4), who (using a picture from ancient Greek worldview) are in the lowest regions of the underworld awaiting judgment.  We will go into more detail about these angels in the chapter on Jude that follows.
The Flood is mentioned more than once in 2 Peter as an example of how, eventually, God both finally brings the judgment he has promised along with salvation for the righteous. Noah is saved while the rest of the world is destroyed (2:5).  Similarly with Sodom and Gomorrah, Lot is saved while those cities were destroyed (2:6-8). The picture Peter gives of Lot is meant to encourage believers who live surrounded by wickedness: "that righteous man, living among them day after day, was tormented in his righteous soul by the lawless deeds he saw and heard" (2:8).
In the same way, Christians can feel powerless when they see things going on around them that they do not have the power to stop. At times we may have to endure people all around us whose conversations are diametrically opposed to God's values. The actions of those around us may be hopelessly evil, with little we can do to prevent it.
We are not used to powerlessness, not in the modern world. We think we should be able to make the world right. We should be stop the wicked from harming others. We should be able to stop injustice. But there is also a time when there is nothing we can do and we have to leave it in God's hands. This is the situation 2 Peter pictures. Until God finally came in judgment, there was nothing Lot could do. 
Even in the Church, Peter hints, there may be those who follow sinful desires and reject authority (2:10). Like Jude, such people might dare engage the supernatural realm--even the evil spiritual realm--disrespectfully in a way not even other angels do.  Such people engage in matters they don't even understand (2:12).
Lord, save us from such overconfidence. How often have I been so sure I understood a situation and yet been completely off? This is especially a danger for parents, who may make an instant assessment of a situation and be completely off. Most of the time, we are not nearly as smart as we think we are. Yet what misplaced confidence there is in the church not only with regard to spiritual things but even with regard to ordinary things!
There may even be people in the Church who "carouse in broad daylight" (2:13). Certainly there are adulterers in our churches, not to mention those who are full of greed (2:14). They sit beside us in church and eat with us in our church fellowships. At some point we should stop and ask ourselves, "Am I one of them?"
The final paragraph of this chapter is sobering indeed. It talks about how people in the Church can ensnare those who are coming to the Church to get away from the ungodliness of the world. "They entice people who are just escaping from those who live in error" (2:18). What a horrible thought! Is it possible that some churches could make those fleeing to Christ for help into "twice as much a child of hell" as before (Matt. 23:15). Could some churches make some people worse off than they were at the beginning (2 Pet. 2:20)?
How would a church do something like this? No doubt there are many ways. One is by "innoculating" a person in relation to God. Say a person is seeking God and comes to your church. But in your church, they do not experience the power of God. Let's say that, in your church, they experience people who are just as "lustful" (2:18), just as selfish and out for themselves as anyone else.
That person might say, "Nah, there's nothing different in the Church than anywhere else" and return to the life they were leading before, like "a dog returns to its vomit" (2:22). But now, they may dismiss God altogether. Before, they may have thought, "I need to try out God sometime." But now they say, "I already tried that God thing and there was nothing to it."
Peter gives these sobering words: "It would have been better for them not to have known the way of righteousness, than to have known it and then to turn their backs on the sacred command that was passed on to them" (2:21). These warnings put an incredible burden on the Church. We represent Christ to the world or, as one old Christian song once put it, "You're the only Jesus some will ever see."
It is a staggering responsibility. How your local church behaves can be the difference in someone's eternal destiny. The answer is not that we make sure we have all the answers or all the right education. The answer is that we are armed with the right attitude. Is our church humble and loving? Do we make visitors feel welcome. Do we treat each other with kindness and with a spirit of true fellowship? Are we pure of heart and generous in motive. As 1 Peter said, "Love covers a multitude of sins" (1 Pet. 4:8).
 The position taken usually relates to whether a given scholar believes 2 Peter was literally written by Peter. Douglas Moo, for example, believes Peter himself wrote 2 Peter and so thinks that Jude is more likely dependent on 2 Peter (2 Peter, Jude [Grand Rapids: Zondervan, 1996]). Most other scholars would see it the other way around, with 2 Peter drawing on Jude.
 This is the only occurrence in the New Testament of a word related to the Greek Tartarus, part of the underworld in ancient Greek worldview.
 This is one of the few items 2 Peter has in common with the content of 1 Peter (see 1 Pet. 3:20).
 We should not be bothered by the fact that Genesis 19 doesn't really bring out this picture of Lot. The New Testament authors make true points sometimes while going beyond what the Old Testament specifically said.
 One interesting difference between Jude and 2 Peter's version of this disrespect is that Jude draws from apocalyptic Jewish literature in his descriptions, books like 1 Enoch and the Assumption of Moses. This is one argument for Jude being the more original, since it is more concrete and context-driven, while 2 Peter 2 is very generic.