Like in his previous letter, Paul explains again that there will be lots of people turning away from God as the world comes to an end.
Paul warns everyone to stay away from all kinds of bad folks including arrogant jerks, greedy people, abusers, disobedient children, liars, and "lovers of pleasure." Well, there goes their weekend plans.
There are also people out there who prey on "silly women" in the church. They make their way into their homes and teach them all kinds of nonsense. But in the end, they've got no clue what they're talking about.
Paul wants Timothy to be just like him: faithful, patient, loving, and all that good stuff. Oh, and don't be afraid of persecutions. Paul's had his share, but in the end, it all turned out fine. (Except of course that last time when he got beheaded.)
Paul says: if you want to follow Jesus, you're gonna get some flack. It's just a fact.
But if Timothy keeps the faith, he'll get through it and help others figure out where they're going wrong in the process. Good luck, Tim.