Selfishness is a consuming and destructive sin. The first and inevitable casualty is the person who manifests it, even if no one else is harmed. Because this sin, like every other, begins in a sinful heart, anyone can commit it—regardless of whether there is an opportunity for it to be outwardly expressed. Even when not outwardly manifested, selfishness breeds anger, resentment, and jealousy. . . .
It is an immeasurable tragedy that modern culture (including much of the church) has, largely through the influence of secular psychology, rejected the divinely commanded principles of humility and selflessness. When the supreme virtue is self-love and the supreme purpose in life is self-fulfillment, mutual respect is replaced by disrespect, mutual service by apathy and indifference, and mutual love by enmity and hatred. 
Christians must not succumb to such a selfish lifestyle, and the other sinful attitudes it breeds. That’s why the apostle Paul points our focus away from ourselves.
Do nothing from selfishness or empty conceit, but with humility of mind regard one another as more important than yourselves; do not merely look out for your own personal interests, but also for the interests of others. Have this attitude in yourselves which was also in Christ Jesus, who, although He existed in the form of God, did not regard equality with God a thing to be grasped, but emptied Himself, taking the form of a bond-servant, and being made in the likeness of men. Being found in appearance as a man, He humbled Himself by becoming obedient to the point of death, even death on a cross