In Philippians 4:8, the apostle Paul instructs us to think about things that are true, honorable, pure, just, lovely, commendable, worthy of praise, and of moral excellence. What are you thinking about? Does it match up well with the list Paul gave us above? If it does, you are doing better than I am. If we’re being honest, most of the thoughts we have are about ourselves: our comfort, pleasure, entertainment, and safety. These are hardly noble thoughts.
To be self-serving is the opposite of behaving honorably. Selfishness stands in direct opposition to every item on that list. Selfishness is the natural offshoot of pride, and prideful people have no place in the Kingdom of God. Consider where all the prideful angels are today. Their fall is a warning beacon for each of us.