It is hard to talk about scripture and special revelation without also mentioning the concept of false teaching. Peter tells his readers that there have always been people claiming to speak for God who were lying. Peter’s readers (including us) can rest assured that that is still the case today.
In a way, we have it a bit easier than Peter’s contemporaries did. We have a closed cannon. While that does not mean that God no longer speaks to His people today, we can rest assured that He does so through His Word, or, in the case that we may feel like we are hearing something from God for our lives we have Scripture to hold that thought up to.
The danger of false teachers is easy to recognize because it always comes in the same form. This is not a case of someone thinking God may be telling them something to obey, and struggling to be sure to do the right thing. False teachers come with new words from God for the body. If you ever hear someone telling you God told them something that the whole body needs to hear or follow, or even if they have a message for you personally, rest assured that you can test that message with Scripture and prayer. Even consider getting a second (or third) opinion. This is the example that is praised in Scripture itself. God doesn’t call on us to obey teachers; we have a responsibility to hear and obey His voice.
At the core of false teaching it is always the same. It is merely a disguised effort to justify disobedience. In all the examples listed by Peter, we see teaching trying to justify sexual sin, but it doesn’t have to be that specific. More often than not in my own personal experience, false teaching seeks to promote inaction. Beware of teaching that encourages you to not do the things you know you need to already be doing.