“Ambition is the mother of all heresies.”
This is Calvin’s remark about Paul’s words in Acts chapter 20, where the Apostle Paul tells the Ephesian elders that after his departure, “fierce wolves” would come in (v.29) or even arise from among their own number, “speaking twisted things, to draw away the disciples after them“ (v.30).
Ambition, either for a personal following, for financial gain, or both (as one often follows the other) may be found at the root of most or even all false teaching. Calvin goes on to say,
“Pure handling of the Scripture aims to give Christ the preeminence, and people cannot appropriate anything for themselves without detracting from the glory of Christ. It follows that those who try to promote their own glory are corrupters of sound doctrine.” (Acts, Crossway Classic Commentary Series, p.339)
So if you are a minister of the gospel of Christ, beware of pride and the temptations of self-promotion. Seek to make much of Christ in your public and private ministry of the Word. It is no wonder that Paul admonished the Ephesian elders to “Be on guard” for themselves before telling them to be on guard for all the flock (v.28, NASB).