Alma 10:12

And now when Amulek had spoken these words, the people began to be astonished, seeing there was more than one witness which testified of the things whereof they were accused, and also of the things which was to come, according to the spirit of prophecy which was in them;

When Amulek spoke these words, the people were amazed. There was more than one person who told them about the bad things they had done. These witnesses also told them about things that would happen in the future. They spoke by the Spirit of prophecy.

When Amulek finished speaking, the crowd was stunned. Now there was more than one witness testifying about what they’d been accused of—and about what was still to come, according to the spirit of prophecy working in them.