At its core, sinfulness is selfishness. It's enthroning yourself - your desires, your needs, your plans - above all else. You may still seek God, but you don't seek Him first. You seek Him second or third or seventh. You may sing "Jesus at the center of it all," but what you really want is for people to bow down to you as you bow down to Christ. It's a subtle form of selfishness that masquerades as spirituality, but it's not Christ-centric. It's me-centric. It's less about us serving His purposes and more about Him serving our purposes.
Mark Batterson, All In: You Are One Decision Away From a Totally Different Life
selfishness, sinfulness