Verses 1-2. Paul continues his mantra of respect. Wherever you find yourself there's always an opportunity to show respect to others. In the previous chapter, Paul said leaders need to respect those under them. Now, Paul says if you are under someone else's authority, you must respect that person. Respect is reciprocal.
Verses 3-6. Paul points out how to spot a false prophet--he respects no one. He is conceited, which means he does not respect other people. However, as a conceited person, his inflated perception of himself is not reality, thus, only serves as another form of disrespect. In the end, this selfishness does not allow this man to understand how things really are. Paul points this out in a truly poetic fashion. The conceited man thinks "godliness" is a tool for his own gain. But the truth is that when one one's goal is real godliness, then they truly reap rewards.
Verses 7-12. Paul continues in similar vein, pointing out the biggest weakness in human history: money. The love of money and all the power that money causes man to do all kinds of evil things. Note that Paul doesn't say "don't do" without giving an alternative. Replace those evil things with wholesome things. Go from destruction to building up.
Verses 13-21. Lest we forget who this is for, lest we think that Paul speaks of his own authority, lest Timothy (or any other leader) blindly follow a mentor, Paul lets us know who is really behind all of these instructions. Our Lord is who is behind everything. Our Lord is the one whom we strive to please. Our Lord is the one we want to be like -- hence the term Godliness. This charge is serious. In light of the seriousness of our Lord, everything that the world considers important suddenly loses gravity. How sad it is that people who profess godliness, miss the mark so egregiously. Finally, a reminder that grace is a key to the Christian life.