How often do we think about giving an account to God? We will all stand before Him and be judged.
One of my friends recently said, "In my mind, through justification, I could do anything!" His point was that we tend to "justify" anything we "want" to do. We have the ability to "reason" ourselves into sinful behavior. We often do things that we know Jesus would not approve.
This chapter clearly states that all of us should be living to please God. Doing what we do to honor Him, not just doing whatever we can justify in our minds. We tend to minimize our sin or lack of commitment and "criticize" the sinfulness and choices of others. Paul is saying: 1. Live to please God, and 2. Worry about yourself and not others.
In the end, God will execute justice.