Alma 30

After Korihor had been struck dumb, he confesses -

"...the devil hath deceived me; for he appeared unto me in the form of an angel, and said unto me: Go and reclaim this people, for they have all gone astray after an unknown God.  And he said unto me: There is no God; yea, and he taught me that which I should say.  And I have taught his words; and I taught them because they were pleasing unto the carnal mind; and I taught them, even until I had much success, insomuch that I verily believed that they were true..."  (Book of Mormon | Alma 30:53)

I've thought how often many have been taught the teachings of Satan contrary to the commandments of God until they too come to believe such falsehoods are true...and then rebel against God and true doctrine.