And I beheld another beast coming up out of the sand; and he had two horns like a lamb, but his mouth was fanged and fiery as the dragon and his body shimmered and burned with great heat while it did hiss like the serpent. -Revised Orange Catholic Bible
We're introduced to The Preacher, who many suspect is Muad'dib, on the steps in front of Alia's Temple.
This is where the line, now famous from the Sci-Fi Channel Mini-Series comes from:
"Did you not hear that man? Blasphemers and idolaters! All of you! The religion of Muad'Dib is not Muad'Dib. He spurns it as he spurns you! Sand will cover this place. Sand will cover you."
They were destroyed because they lied pretentiously. Have no fear that my wrath
will fall upon you because of your innocent mistakes. ~Leto II, God Emperor