Peter wrote the second letter 3 yrs. later encountering the danger of false teachers. The word knowledge in the Bible is “experiential knowledge” not just head knowledge. Many people know things, but Never Experience it. Reminds us that we are born again, the Holy Spirit is in you. To live a Christ-like life we also need to work on virtue, knowledge, self-control, steadfastness, loyalty, godliness, brotherly affection, & love. 

This letter warns us how to identify false teachers. They tell people what they like to hear. More people come, more offerings/tithes. It’s called "marketing in modern terms". We see heresies & persecutions everywhere, it has become normal in Christianity. But God will deal with them. He will rescue His own. 

God is giving time to people to repent & be saved. We don't need to worry about what's happening on this earth. God wins always. “By me, all things consist.” (Col 1:17). His plans are always higher than ours. This is a temporary place, we are headed to the New heaven & New earth to enjoy eternity in a real place. A living hope. God bless you!