Make my joy complete by being of the same mind, maintaining the same love, united in spirit, intent on one purpose. Do nothing from selfishness or empty conceit, but with humility of mind regard one another as more important than yourselves.
In verse 3, Paul went deeper and stresses that we must have humility of mind. Paul contrasted humility of mind to selfishness and empty conceit. The Greek word for “selfishness” in this verse is erithía, which means “ambition, self-seeking, rivalry, self-will being an underlying idea in the word” (Vine, 2:68). It implies seeking after position and glory.
Adapted from Philippians: That I May Gain Christ, page 98.