Alma 30:46 - 30:50
Alma 30:46 And now it came to pass that Alma said unto him: Behold, I am grieved because of the hardness of your heart, yea, that ye will still resist the spirit of the truth, that thy soul may be destroyed.
Alma is very disappointed in Korihor's attitude. He grieves that he cannot allow the spirit of truth to have influence over him even to the point of allowing himself to be destroyed.
Alma 30:47 But behold, it is better that thy soul should be lost than that thou shouldst be the means of bringing many souls down to destruction, by thy lying and by thy flattering words; therefore if thou shalt deny again, behold God shall smite thee, that thou shalt become dumb, that thou shalt never open thy mouth any more, that thou shalt not deceive this people any more.
Alma now says that it is better that he be destroyed rather than influence more gullible people to come to his way of thinking. Alma gives him one more chance to change his attitude, but if he insists on a sign, then the Lord will strike him dumb so that he cannot speak. His days of influencing people to disbelieve in God will be over.
Alma 30:48 Now Korihor said unto him: I do not deny the existence of a God, but I do not believe that there is a God; and I say also, that ye do not know that there is a God; and except ye show me a sign, I will not believe.
Korihor is beginning to fear that Alma can do what he says and replies that he will not say that is no God, but that he does not believe there is a God. Again he accuses Alma of not really know that there is a God and says if he is not given a sign he will not believe.
Alma 30:49 Now Alma said unto him: This will I give unto thee for a sign, that thou shalt be struck dumb, according to my words; and I say, that in the name of God, ye shall be struck dumb, that ye shall no more have utterance.
So Alma gives Korihor the wanted sign. He is struck dumb and can no longer speak.
Alma 30:50 Now when Alma had said these words, Korihor was struck dumb, that he could not have utterance, according to the words of Alma.
Korihor is now struck dumb and cannot speak.