Commentaries:
A spiritually immature person in an office of authority like this will follow the same course that Satan took. He will get a big head and try to grasp beyond his position.
Richard T. Ritenbaugh
Countering Presumptuousness
Self-will is insisting stubbornly and arrogantly on one's way, as opposed to following the will of God. Paul states that a minister of God must not allow himself to be self-willed but must be led by and do God's will. What kind of minister would a person with false pride and stubbornness make?
Martin G. Collins
Overcoming (Part 4): Self-Will