Warnings to spiritual leaders and teachers need to come from one whose motive is love (from and for God), a pure heart, clear conscience (no alterior motive), and genuine trust in God.
The Holy Spirit has expressly warned the body of Christ that in the LATTER TIMES some in the body will take up a position (doctrinal) away from the faith (Gospel of grace and faith in Jesus Christ) paying full attention to the erroneous teachings brought by demons --- those false teachers will be play acting as they teach erors because their conscience is cauterized (destroying spiritual nerve endings).
