A rendering which obscures the meaning. The words point forward to the next two clauses. The reason of your error is your ignorance of the scriptures and of the power of God. Hence Rev., correctly, Is it not for this cause that ye err?
Err (πλανᾶσθε)
Lit., wander out of the way. Compare Latin errare. Of the wandering sheep, Mat 18:12; 1Pe 2:25. Of the martyrs wandering in the deserts, Heb 11:38. Often rendered in the New Testament deceive. See Mar 13:5, Mar 13:6. Compare ἀστέρες πλανῆται, wandering stars (Jud 1:13), from which our word planet.