the chief judge - bound by his own words

The people of Amonihah had just kicked out the men that believed in God and killed their women and children.  The chief judge says to Alma and Amulek, 

24 If ye have the power of God deliver yourselves from these bands, and then we will believe that the Lord will destroy this people according to your words.

Then they all hit Alma and Amulek.  Then Alma says,

26 ... O Lord, give us strength according to our faith which is in Christ, even unto deliverance.  And they broke the cords with which they were bound;  ...

So Alma and Amulek just did exactly what the chief judge said, so now he is bound by his own words to believe that the Lord will destroy the people.  So it makes perfect sense that...

"... when the people saw this, they began to flee, for the fear of destruction had come upon them."

(Book of Mormon | Alma 14:24 - 26)