They were struck dumb

1. Alma 30: 50
     50 Now when Alma had said these words, Korihor was struck dumb, that he could not have utterance, according to the words of Alma.
2. Hel. 5: 25
     25 For they saw that the Lamanites durst not lay their hands upon them; neither durst they come near unto them, but stood as if they were struck dumb with amazement.