"Let us not be desirous of vain glory, provoking one another, envying one another." Galatians 5:26
"Vain Glory" is another term for selfish ambition. Paul clarifies what type of selfishness he's getting at: the kind that intentionally degrades and harms people - specifically other Christians. It does something for our ego to rub another person's face in their faults or sins. When we are offended by another, our natural reaction is retaliation. We want to punish, irritate, and provoke that person - not so much to get them to change - we do this because it simply makes us feel better. Paul strongly warns against this type of retaliation. It only does more damage because it is selfishly motivated.
Secondly, he warns us to avoid envying one another. This is the opposite extreme. We envy others when we constantly feel inferior. We internally beat ourselves up because we're not as talented, spiritual, skinny, athletic, wealthy, disciplined, or happy as someone else appears to be. This act of envy is actually self-centeredness. A tendency to covet others' lives can quickly turn them into idols and their good traits into objects of lust.
These unhealthy opposites are symptoms of the same problem: self-centered ambition. This problem will be yours and mine when we choose not to walk in the Spirit. "God, help me to see others with eyes of compassion and care. When I'm offended, help me to turn the other cheek and forgive instead of my tendency to retaliate. Remind me to simply be blessed by others' strengths when I am tempted to covet and envy their strengths. Produce your spiritual fruit in me today."